Doctor Who reveals what's behind closed (Tardis) doors on The Graham Norton Show

Graham Norton talks to David "Doctor Who" Tennant about his behind-the-scenes exploits with fellow time traveller John Barrowman as the iconic BBC series is set to return for a new series this weekend.

"We get very competitive about farting in the tardis..." David jokes on BBC Two's Graham Norton Show.

"...farting before performing is a kind of exorcism. John feels the same way ... it's our Glasgow heritage."

But he says new co-star Freema Agyeman, who joins the Doctor as assistant Martha Jones, was less than impressed: "Freema really didn't like it, which spurred us on."

"Seriously though, it's the best job in the world, I'm having a ball. It's a big responsibility, people are very enthusiastic about it, and that can be a bit of an undertaking."

And as for the rumoured Doctor nuptials, David says: "It's very difficult to answer – he doesn't not get married."

Graham also welcomes to the show comedienne Jo Brand, who joins David in reminiscing about their separate exploits for this year's Comic Relief.

Jo says about her appearance on Comic Relief Does The Apprentice: "Trinny Woodall knows everyone in Belgravia who earns more than £10million a year so she got on the phone and the rest of us just went to the pub, it was great!"

David, who had a walk-on as part of the audience in The Proclaimers' Comic Relief video, reveals he didn't actually meet his favourite group on the day – "Matt Lucas knew I was a big Proclaimers fan ... I didn't really know what I was turning up for and it was an interesting collection of people ... but [the band] had been and gone by the time I arrived.

"I was devastated, so tonight I'm a bit over-excited..." – and proceeds to meet his musical heroes on the show when The Proclaimers perform their number one hit I'm Gonna Be 500 Miles.

Doctor Who returns to BBC One on Saturday 31 March 2007 at 7pm.

The Graham Norton Show is a So Television production for BBC Two.

The Graham Norton Show, 10.00pm, Thursday 29 March 2007, BBC Two (extended repeat, Sunday, 11.30pm)