Dawn French’s memoir Dear Fatty made me cry, caused twisted knots of pain more than laughter. French thinks that’s a good thing. It certainly made her cry when she was writing it.

The book takes the form of various letters to those who have touched her over the years – and most are to her father, who attached a hosepipe to the exhaust of his car and killed himself when she was 19.

A former RAF pilot, Denys French had tried to make a go of running a newsagent’s shop but couldn’t deal with bouts of crippling depression. The book tells him about all the important events in Dawn’s life that he missed. He is missed on her wedding day to Lenny Henry. He is missed upon the arrival of Billie, the daughter whom French and Henry adopted. He is missed at every family moment and every personal and public achievement. You feel those missing years, but you also feel their love for each other.

“I often think what a shame it is that he missed out on this or that,” says French. “Anyone who’s lost a parent when they are young, I think, has that feeling. You want to say: this is what I’ve done.”

There are also letters to her mother, Roma, who rebuilt her life in an extraordinary way after Denys’s death. Roma could turn her hand to almost anything – poodle-clipping, accountancy and, most recently, helping drug-addicted mothers to keep their children during recovery.

French wrote her book with a pencil and pad because “I’ve never used a computer”. There are comic interludes – such as her letters to Madonna. It’s a long-running joke between French and her great friend and comedy partner Jennifer Saunders that Madonna never agreed to appear in one of their television shows. There’s a description of the singer’s arms that is unlikely to please her: “Muscly and veiny, like a drawing of a body you get on the side of headache tablet boxes.”

The book was very hard to write. French found it difficult to reveal much of herself to people she didn’t know, yet she was aware that the point of a memoir is to look for a certain truth. She even hired someone to interview both her mother and her 100-year-old grandmother so that she could align her memories with the facts.

In the end, the only way she could write it was to address the players in her life, which also gave her a title.

“I knew I’d be writing to Fatty [her nickname for Saunders] and I thought I’d call the book Dear Fatty because I’ve always embraced any fat references and it amuses me that I call her Fatty when I’m the fat one. It’s always been a joke between us, with great affection. Although the letters are mainly to my dad, of course – but Dear Dad sounded a bit dull.”

There’s a chirpiness in the rhythm in the way she talks that only seems to accentuate the sadness and tragedy.

Her father adored her and was always the one to tell her she was gorgeous. He was wonderfully protective and never let her down until, perhaps, the day he took his own life. French was about to start college the following week. She remembers saying a hasty goodbye to him as she stepped out for an evening with her boyfriend, but can’t remember whether or not her father said “I love you” as she left.

After his death, she asked her mother: “Do you mind if I don’t go to college? I’m in pain. I’d quite like to stay home and be cuddled for a year.” Roma, however, was having none of it.

“She said, ‘You are going to go. You must go’. She was incredible. She just got on with it.”

French remembers that her father occasionally had headaches and had to have a lie-down, but she and her brother Gary weren’t ever aware that he suffered from depression. “I don’t remember it and that’s how he’d want it. Our whole childhood was fine because he hid it. Between the two of them, my parents hid it.

“He’d made his first suicide attempt when he was about 16, so he definitely had these awful bouts of very clinical depression. But they were the bouts that come and go, so he might be fine for a few years . . . but then there would be another visitation.”

But “he couldn’t really go and get help, could he? It was a shameful thing, mental illness. He wouldn’t dream of asking for help because nobody could at that time”.

She adds: “If I see signs in anybody now, I’m the first to boss people to tell them to get help. I refuse to stand on the sidelines and watch anybody in pain.”

When her husband started to go off the rails, he immediately received help in the form of a stay at the Priory. She is all too aware that if her father had been able to talk about his problems, and if there had been a Priory available for him in 1977, he might not have died.

What lives on is a legacy of confidence that her father gave her and the ability to make the most of every day. It must have helped her through her husband’s crisis, which was also a crisis in their marriage.

“He got help. Len is not a depressive, actually, but he was seriously sad for a lot of reasons. Between 40 and 50 is a time when you start to reevaluate stuff – and then his mother died. She had been dying for several years and that had been hard for him. I don’t think he made sense of it all till she’d gone. It was a real slippery old snake, that grief.

“He was questioning everything: whether he wanted to continue in his career, who he was. I look at who he is now – and here we are, down the line. We just needed to kickstart into that next bit. I knew he needed to get proper help – and when he did get it, I’m thinking: hurray, hurray, this is what my dad couldn’t do. And Len is not ashamed to do that, to talk to anybody.”

For her, the worst moment came one night in 1999 when he was away on tour and two men in raincoats appeared on her doorstep at 10.30pm. “I thought it was the police and I thought, ‘They’re coming to sit me down, like on The Bill, to say he’d died’.”

Did you think he’d killed himself? “Definitely not. I thought there’d been an accident. But instead, these people were journalists. They were doorsteppers.” The doorsteppers informed her that Lenny had been stepping out of line with a blonde. What did she have to say about that?

In fact, she was relieved to hear it. “The great thing is that you go from thinking ‘he’s dead’ to ‘oh, he’s been a bit stupid.’”

Afterwards, French and Henry talked and talked. They wanted to get all their cards on the table. Is that because she feared what else might be going on?

“I don’t think so. I just think what happened was something we would not normally bother to talk about – but it had to be talked about. The control was outside of us. Let’s fess everything up because they [the press] are going to make it toxic – so let’s make sure there’s nothing toxic inside our relationship.

“Some people have a relationship where everything is completely out and we don’t really have a relationship like that. It’s kind of grown-up. We are around interesting people and sometimes they are going to be interested in you – and how you behave around that is your business. But I felt we had both better know absolutely everything because I didn’t want to be reading in a paper what I didn’t already know. It’s an odd experience. You feel bullied in a way that you can’t answer to. Plus a lot of untruths get written.”

The crisis talks with Lenny were more amusing than cathartic, she confesses: “It was funny – because we started to invent situations because the stuff we really had to say was a bit dull.”

The catalyst for her book was a biography of her written by a journalist who had never met her yet dug into the circumstances of Billie’s adoption. It takes a lot to crack French’s bouncy veneer, but she was boiling mad and fiercely protective of her daughter.

The result is a memoir in which she sends herself up and points out her own flaws before anyone else can get in.

“I didn’t want to write a book that cleverly sidesteps everything that’s happened to me,” she says. “I don’t expect people to pay for a book that I say is about me, then it isn’t. So I wrote a book that I thought was truthful. Anybody who gets to 50 has had sadnesses, betrayals – and, yes, has been heartbroken. I don’t think my dreams are any different from anybody else’s.”

For the first time she writes about her first proper boyfriend, who helped her to cope with her father’s death. She was engaged to him when she was 19. He was in the navy then.

After leaving the forces he went to work in India for a tea company, hired servants and grew progressively more right-wing while she defined herself as left-wing. Just before they were due to be married, she visited him in Sri Lanka, a new posting where they planned to live after the wedding. He introduced her to his expat friends; but next day, in a heart-to-heart discussion about the way his life had changed, he confessed that he had been sleeping with one of them, a nurse.

French fled, blubbing, back to England and the remaining months of her course at the Central School of Speech and Drama in London with “Jennifer Saunders, my beloved Fatty”, a fellow student whom she had initially branded a “snobby git” before discovering that they could make each other laugh uproariously.

Their friendship became a lifelong bond; but people still ask whether French was jealous when Saunders developed Absolutely Fabulous – in which she starred with Joanna Lumley – from a 14-minute sketch into a long-running series.

The truth is that French was grateful. They had been about to start a new French and Saunders show when she got the call that she had been long awaiting from an adoption agency. Suddenly the right baby had been found and she had to collect her and become an instant mother. And it all had to be done in secret: the last thing she wanted was press coverage of her difficult path to motherhood.

“I’d had two miscarriages,” she says. “One as a result of IVF and one before that. I have never talked [publicly] about IVF before because why would you want to talk about your insides to somebody? I’ve got friends I talked to, if I needed to talk. But as I was writing the book I talked about IVF because it was something Len and I went through together and which we survived. It was not easy; it was gruelling. Like everything in life, people cope in different ways; but because we didn’t want to be in the press, we were very quiet and secretive. And the same was true when we went for the adoption. For the first seven months of Billie’s life she was completely secret in our home.”

Her letters to Billie are just raw love. She talks about how beautiful she was as a baby but how she can be full of rage: “She’s full of hormones, anger and delight. Most of my mates have got teenage kids, so I don’t think I’m going through anything that anybody else isn’t. Her teenagehood is different to my teenagehood. I don’t think I was as angry and I don’t think I would have considered that an option. But they’ve got much more access to display their furies these days.”

Does she think that Billie’s anger is anything to do with being adopted? “With adopted kids it’s dangerous to assume that everything they are is because of adoption. I have no idea who she would be if she was not adopted. But what I have to accept is that, when you are adopted, there are questions that are infuriating not to have the answer to. She has to live with some things that I don’t have to; I have to grant her that and support her.”

Does Billie know about the circumstances of her adoption? “She knows everything I know. There are things that are private when you’re adopted – not secret, but private – and not for anyone else to interfere with.”

She believes passionately that timing is important when revealing such information to an adopted child – one of the reasons she was so furious with the journalist who tried to put it all in the public domain.

French’s own teenage rage was definitely contained, if it existed at all. She was once accused of shoplifting during a foray with a friend to the local Coop, while she was at boarding school. The store detective accused them both of stealing a pair of tights; then he gave them the option of calling in the police – which would have meant being found out for leaving the school grounds without permission – or submitting to a full body search, there and then.

As the security guard fumbled in their bras and knickers, each thought the other must have stolen the pair of American tans. Of course, neither of them had. It had been an excuse for the security guard to interfere with them. But French is more horrified at the thought of anything like this possibly happening to her daughter than she is about her own experience.

“I don’t think it scarred me. I’m sure it affected me in the short term. But I don’t think it affected my sex life or anything like that.” French is clearly not the type of girl to crumble because of a fumble.

The book is a testament to her emotional fortitude. In a letter to Hannah, her niece, she writes extremely funnily about her body and particularly about being endowed with more than her fair share of abundant bosom: “Every time I see a flat-fronted woman, I want to apologise for my seemingly appalling greed.”

French is very close to Hannah, whom she sees as a “mini me”. She says: “I wouldn’t say we’re physically exactly the same, but there is something about her that is very similar. The whole family knows it. I’m drawn to her because I understand her. I can read her because she has the same processes that I had.

“I recognise all the things about her that are familiar, although she will find it a huge relief that her mum’s genes are taller and much thinner and not as squat as our side of the family who are teeny and wide like Weebles.”

She assures Hannah that, if you like who you are and your body, other people will like it as well. “But it has to be the truth,” she tells me. “It can’t be a fake thing. Although what you can do is pretend when you get a blip in confidence; sometimes you can do some pretending and swing it so that you are confident.

“I’ve done that quite a lot in my life. Not necessarily about weight issues but other stuff where you don’t know how to cope so you pretend to be somebody who can cope.

“I just wanted to tell that to her and to my own kid, because they live with pressures that I did not to be a size 2. Just imagine what it is like for them. Much worse.”

That is not to say that French herself has never suffered a blip of confidence about her body. She decided to slim for her wedding – took pills, had injections and ended up with bad breath and a size 12 body. Even Lenny Henry was puzzled. “Who are you doing this for?” he asked her.

The friend who made her wedding dress had to take it in twice. “It was that fabulous emotional cliché: when I tried it on for the final time, my mum burst into tears, we were all crying. I was delighted that we had to take it in. I didn’t have a second thought about what it would be like for my friend to unpick and sew up a dress the night before a wedding. It’s the only time that I’ve had that blip. Very possibly because there is no imagery for big brides, so it’s hard to relate to them.” Her father had always been the person to tell her that she looked beautiful, even in suede hotpants. “Jennifer and I were talking the other day. When we look at photos of ourselves when we were younger, we were gorgeous. It wasn’t just a helpful dad taking pity on you. It wasn’t fake.

“My daughter now is breath-takingly beautiful. She has had people in bands ask her to marry them. But I’m not sure if she translates that into ‘therefore I must be pretty’. She doesn’t think she is and that’s a fact. So I hear myself doing all the stuff my parents did. In the end it will work.”

You get the sense that, like many confident people, French is a doer who is unfazed by small setbacks. At the moment she and her family are in the throes of a long-awaited house move from Berkshire to Corn-wall. I ask how Henry will feel about living in a village that has – of all things – an annual Darkie Day.

“In Jennifer’s village they do a thing where they put flaming tar barrels on their back and run up the street. This is because we are British and we love these kinds of myths. Still, I wish it wasn’t called that.”

Do people dress up like black and white minstrels on Darkie Day? She doesn’t think so. She reminds me that when they lived in London there were more obvious examples of racism: excrement on their doorstep, horrible graffiti on the walls and a burning rag put through their letter box at night.

There is a sense that going to Corn-wall is going back to where she belongs. All her family are from there, even though French herself was born in north Wales: “We have been a long time in deciding. We’ve outgrown living here. Len didn’t feel a great pull back to the West Midlands or to the Caribbean. He doesn’t feel a pull to anywhere.” So Henry was happy to go with Dawn’s very strong pull.

Her book encompasses lots of goodbyes. Goodbye to Berkshire. Goodbye to her massively popular sitcom, The Vicar of Dibley. Goodbye to French and Saunders (the duo begin their final West End run on October 15). And goodbye to chocolate-coloured hair; it’s now a tawny caramel because French thinks lighter colours are better suited to ageing faces.

On a different level the book is also a goodbye to her father all over again. I wonder if it was this series of goodbyes that gave her the notion that she would die young, as she told me last time we met.

“I can work out most things that are my demons,” she replies. “But that one’s bizarre – especially as last week it was my granny’s birthday and she was 100.”

She takes out her pen to sign my copy of her book: “To Chrissy, still not dead.”

© Chrissy Iley 2008

Dear Fatty is published by Century on October 9 at £18.99. French and Saunders: Still Alive! is at Theatre Royal Drury Lane from October 15 (0844 579 0089)

Explore Women

• Fashion

• Beauty

• Diet & Fitness

• Relationships

• Families

• Celebrity

• The Way We Live

• Horoscopes

Times recommends

• Are eldest children really a cut above?
• Peaches Geldof: censored
• Top 10 style-setting films of all time