Billie Piper was worried 'Doctor Who' would ''die a death''.The 30-year-old actress - who was the Time Lord's companion Rose Tyler for the first two series and again in the fourth season - admits she struggled with the tough filming schedule initially when the sci-fi show relaunched in 2005, and wondered whether it would be 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.''