Billie Piper quitting 'Doctor Who'?

Billie Piper has decided to quit Doctor Who, according to a report in The Mirror today.

The actress, who plays sidekick Rose Tyler, will not be returning for a third series due to fears that she may become typecast.

"She wants to strike while the iron's hot and make a big name for herself while she's so popular," a source told the newspaper. "She feels her profile will go down if the series isn't as big the third time around.

"The BBC are auditioning other girls to take over. They want to have the next actress all lined up when they announce Billie's departure. They are quite miffed about her decision. The casting people have been conducting secret auditions with a small number of actresses and keeping it very, very quiet.

"They are after a relative newcomer so this is the role which puts her in the public eye. It also means she's less likely to get bored after one series."

Piper is currently filming for series two of the sci-fi show, alongside new Time Lord David Tennant.