5. Billie Piper
Rose Tyler, I- didnt know you were a British pop star! Any sci-fi fan worth their salt knows Billie Piper as the spunky Rose Tyler, companion to the 9th and 10th iterations of the Doctor from the venerable British series Doctor Who. Before she travelled all of space and time (and got
very friendly with future Doctor Matt Smith as the lead in
Secret Diary of a Callgirl), Billie Piper conquered the British pop charts. Her musical career (begun at age 15 and short-lived by choice), nonetheless produced three albums, several hit singles, and gave Piper the distinction of becoming the youngest artist ever to top the UK pop charts. http://youtu.be/xhz27-BCj9o
(Source: http://www.guardian.co.uk/uk/2008/jan/04/theatre.arts Billie Piper Profile)