Billie Piper has admitted to being worried 'Doctor Who' would "die a death".
Admitting she struggled while playing the part of Rose Tyler - the Time Lord's companion - she wondered whether the role was really worth the effort.
She said: "At first, I didn't know whether the show as going to be a success or die a death. It was such a hard shoot - nine months, with pretty much everyone using CGI for the first time. There were times when I thought, 'Is this ever going to pay off?'
"But it did. I remember being in a London hotel for the launch of the first episode. There was a buzz; it was thrilling. I called a friend and said, 'I'm going to remember this feeling for the rest of my life.' "
The role of the Doctor's companion Rose helped launch Billie's acting career, and while fans were initially sceptical of the then-singer being cast in the show, she thinks they quickly grew to appreciate her.
Speaking to The Guardian Weekend magazine, she added: "'Doctor Who' launched my acting career. I was in this awful transitional period, going from singing to acting, so getting the part of Rose Tyler felt like a real vote of confidence.
"I'm not sure the fans were as happy - loads seemed hacked off, as they often are about change - but they soon seemed to accept me.
"I've signed quite a few fans' bodies over the years, but my fan mail has been very gentle - these are smart people, with sci-fi intellects."
Tagged in Billie Piper