If his chat show is anything to go by, Graham Norton could keep up his chirpy line in celeb quizzing in his sleep. Which is just as well, for tonight he embarks on a mammoth six-hour chat-athon in a Guinness Book of World Records bid to pose the most questions asked on a TV chat show. All in aid of Comic Relief. Our Graham's not flying solo, though - Frank Skinner and Terry Wogan are on the subs bench and there's music from Example, Paloma Faith, Hurts and Laura Mvula. Celeb guests chatting along include Louis Smith, Martin Freeman, Russell Tovey, Heston Blumenthal and Sarah Millican.

Norton foregoes the usual physical challenges beloved of Comic Relief for a more sedentary affair: attempting to set the Guinness world record for most questions asked on a TV chat show, which should see him broadcasting into the wee hours of Friday morning. We can only hope that Graham also dispenses with his usual tipple of wine with guests, otherwise this chatathon is going to get very messy.

So far guests announced as appearing on the sofa include Ronnie Corbett, RT's Sarah Millican, Martin Freeman, Elle Macpherson, James Nesbitt, Louis Smith, Heston Blumenthal, Warwick Davis, Russell Tovey and Jimmy Carr, though you wouldn't bet against an American superstar or two turning up, too. Music acts will include Example, Paloma Faith, Hurts and Laura Mvula.

Graham will be assisted by co-hosts Terry Wogan, Frank Skinner and Nick Grimshaw, and viewers can help, too, by submitting questions via Twitter and Facebook. And by donating money.

He's made a big impact as a star in such movies as Boogie Nights, The Departed and The Fighter but for some of us, Mark Wahlberg will always be Marky Mark. Chances are, though, that Graham Norton won't have the front to request a pose in shiny white Calvins - Wahlberg is very serious about his acting and is in Britain to talk about latest film Broken City, a crime thriller co-starring Russell Crowe. Now that must have been a punchy set. There's more movie talk with Shame star Michael Fassbender, soon to be seen in a live-action take on gaming sensation Assassin's Creed, plus laughs from Sarah Silverman and music from Laura Mvula.