Smith warned off dating co-stars?

Doctor Who writer Steven Moffat has joked that he told Matt Smith not to get too friendly with his female co-stars.

Steven apparently warned the TV heartthrob about dating his sidekicks on the BBC One show, which is now entering its seventh series.

The Sun reports that the writer quipped at the series premiere: "I think I may have started with the words: 'Strictly between you and I...'"

Karen Gillan, who plays the Timelord's companion Amy Pond, interjected: "This is so embarrassing!" and Steven added: "Heavens! I plead the fifth. Can I please be extracted from this?"

Matt - who is rumoured to have rekindled his romance with model Daisy Lowe - apparently insisted there had never been any flicker of romance between him and Karen.

"Absolutely not. No, no, no. We're professionals!"

Karen is quitting the show this series, and will be replaced by former Emmerdale star Jenna-Louise Coleman.

Matt said: "That is what the show is about, evolution and regeneration, and we now have Jenna, who is lovely and great."