Billie Piper is still only 24. But, having crammed a pop career, a battle against anorexia, marriage to Chris Evans and a stint as Doctor Who's sexiest, spikiest assistant ever into her short life, she has a maturity far beyond her years.

Material aplenty for an autobiography already, then. And she has duly obliged.

Growing Pains reveals her burning ambition from childhood and her insatiable workaholic mentality, from first attending theatre school at 12 to becoming a pop star at 15.

Her first single, Because We Want To, went straight to number one, followed by Girlfriend, which also topped the charts.

Her hectic work schedule - 18-hour days, recording, making videos and touring - meant her life became far removed from the normality of her family and friends in Swindon.

It was then the feelings of self-doubt engulfed her. Was she thin enough, could she sing well enough, could she pull off live performances?

"The anorexia turned into something which was about me losing control of every aspect of my life and knowing that the one thing people couldn't force me to do was eat," she says. She lived on a diet of cigarettes, coffee and diet Coke. "I went down to about seven stones... At the time, I thought I looked fabulous but I look back and realise I looked like a freak."

Matters reached crisis point in 1999 when, in a hotel room in Chicago, she made a feeble suicide attempt with a handful of Melatonin, which she thought were sleeping tablets, before calling her parents in desperation.

It was a cry for help, she admits now.

Billie had begun her recovery when she met Chris Evans as a guest on his Channel 4 TFI Friday show. She was 18 and he was 34. Shortly afterwards she appeared on his radio show.

"He was my knight in shining armour," she laughs. "He has this zest for life that very few people have."

He wasn't aware of her anorexia initially. "Whenever we were out together I would eat. It changed just like that," she says, snapping her fingers. "He made me feel so sexy and happy about myself. That's his gift."

They married in Las Vegas in 2001 and enjoyed two years off when her pop career waned and he fell out with Virgin.

That phase came to a natural end when both of them decided they wanted to return to work. They came back to live in their big house in Surrey. She cooked, grew vegetables and went to bed at 9pm.

But she also relaunched her acting career, gaining the part of Rose Tyler in Doctor Who.

"It's really hard to say what went wrong," she says. "He didn't have an affair, I didn't have an affair, he didn't abuse me. We had been inseparable and suddenly we never saw each other."

They remain best mates, however, even though Piper now lives with her boyfriend, Amadu, a 28-year-old lawyer she met at Virgin years ago.

Meanwhile, her acting career is going from strength to strength.

She'll be appearing in a TV adaptation of Philip Pullman's The Ruby In The Smoke at Christmas, and is playing Fanny Price in Mansfield Park, filmed at Newby Hall, near Ripon, as part of ITV's forthcoming Jane Austen season.

She is determined she is not going to burn out again, however.

"I learned quite a few lessons. I can just work hard on something I really love and then go and have dinner with my mates."

Growing Pains, by Billie Piper, is published by Hodder & Stoughton, priced £18.99.