Billie Piper has said she felt like a "charlatan" when she was a pop star in her teens.
She told BBC Radio 4's Desert Island Discs that acting was always her passion and she felt she had limited musical abilities.
Piper, 38, who now works as an actress, shot to fame in her teenage years with hits including Because We Want To, and lived in London away from her parents for several years before turning 18.
She said she felt like a "salesperson for other people's music".
"I always felt like a charlatan because I loved singing but I didn't have the strongest voice, I didn't write songs, I didn't play or write music," she added.
"Acting was what I wanted to do most and on some level I was acting my way through it because it became too hard to uphold."
She said being cast in Doctor Who as Rose Tyler was "great in many ways because I was doing what I felt like I was born to do on some level".
The actress joined the programme in 2005 as the Time Lord's companion.
"It was a very exciting and satisfying time because it was hard to get an acting job with my history, first as a pop star then as this sort of burnt-out child star, which is how I think I was painted," Piper said.
She added she thinks that perception of her persisted until "quite recently".
The actress, who is from Swindon, said she was "desperate to get out" of the "small town environment" when she was younger.
She said she did not "like what I saw for women in that place".
"I didn't want to just leave all my ambitions and desires at the door to sort of raise kids and serve men," she said.
Piper also said her parents "always supported me in everything I wanted to do, which was a lot".
She added: "I had a lot of fire in my belly as a kid about things I wanted to do, about things I loved and things I wanted to pursue and my mum, I feel like she was always amazed by that and my dad would champion it all the way."
Piper shares sons Winston James and Eugene Pip with her ex-husband and actor-turned-politician Laurence Fox, who is standing to be Mayor of London.
She is also mother to Tallulah, who she shares with her partner Johnny Lloyd, the former singer for rock band Tribes.
Billie Piper's episode of Desert Island Discs was airing on BBC Radio 4 and BBC Sounds today.