If you could write a letter to your 16-year-old self, what would it say? Would you impart sage advice, would you tell yourself to buy shares in Google, or would you just say "don't worry so much"? This is the intriguing proposition behind a new book Dear Me, a collection of letters from celebrities, such as Stephen Fry and Yoko Ono, to their teenage precursors. With further contributions from Annie Lennox, Jackie Collins, Jonathan Ross and Sir Ranulph Fiennes, it would be easy to dismiss Dear Me as mere stocking-filler fodder. Nothing could be further from the truth. Via its website, Dear Me has taken on a life of its own, with members of the public who have loved the book submitting their own letters in droves. As the editor, Joseph Galliano, admits, Dear Me is not just a throwaway chance to delve into the minds of Oscar-winners or pop stars. It has a far deeper resonance.
"It's thrilling to see how deeply people have bought into it," he says. "I think that's because it taps into something we all share. Ask anybody about their teenage years and they will tell you that they were in some way challenging, but there's also a warm nostalgia in looking back at the person you were." Although comedians such as Paul O'Grady and Alan Carr mercilessly laugh at their younger selves (as O'Grady writes: "The hair ... does it have to be so bouffant?") there is also an aching sadness to many of the contributions. Emma Thompson's entry - "When he says he doesn't love you, believe him. He doesn't" - is poignant, heart-rending stuff.
"It was incredible, getting these letters that could make you laugh, make you cry, make you think," Galliano remembers. "Generally people were telling themselves to hang on in there, that it might be difficult at the moment, but everything was going to be OK. The big messages were ones that came with the benefit of hindsight and age: be bold, embrace life, go for it. But there were so many, too, which simply said: 'Tell your family you love them'."
Of course, if you boil Dear Me down too much, it is completely nonsensical: these letters will never be read by the writers' 16-year-old selves. But it is the process of analysing a life, of trying to make sense of it via a letter, that Galliano thinks is important. "I think this works for someone coming up to 16 as much as it does for someone at the other end of their life," he says. "We've all been that age, and the book really covers both youth and what it means to grow older, too. Actually writing one of these letters is therapeutic -an exercise in taking stock. You can reassess things in your life that you might have been hard on yourself about at the time, and through writing a letter you look at them again through a kinder, older world view. You end up thinking maybe you weren't so geeky, daft and unlovable as you thought."
In the book, the letters, on the whole, are printed as they were written and posted. This was important because Galliano is also celebrating the lost art of the letter in an age of e-mail. He has always been a letter writer, and can trace his love of the form right back to the beautifully handwritten notes his mother would leave or send him. "It's ingrained in my personality," he says. "If you sit down with a pen and write on paper, it's a more direct route to your brain. It's a much closer relationship than you have with a keyboard: when you hold a pen, it's physically connected to you, somehow."
Galliano worries that he is making Dear Me sound very worthy. But it is also fun. He chuckles when I ask him about Patsy Kensit's entry. "You adore music more than anything in the world," writes the actress who has been married to Jim Kerr from Simple Minds and Oasis's Liam Gallagher. "But that doesn't mean you have to marry every lead singer of every band you have a poster of." Galliano laughs. "That was literally the first thing she said to me when we were discussing the project. She prevaricated for a few weeks, and ended up writing exactly what she told me. But you do find yourself being really truthful when you try writing these letters. I know I did."
So why the age 16 when, essentially, this is an exercise in thinking about who we are now as much as what we were like then? "Because it's such an interesting age," he says. "It's a time when we think we're adults but really, we're still children. Life stretches ahead of us, pregnant with possibility," Galliano says. Dear Me (Simon & Schuster) is out now. £1 (Dh6) of every book sale goes to the Elton John Aids Foundation.