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.

The inanities of the world of the minor celebrity are nicely skewered in this spiky mockumentary starring Brenda Gilhooly as the busty Gayle Tuesday, a former Page 3 girl desperate to break into TV. There's a tragic kind of humour to the dim and deluded Tuesday as she attempts to get noticed once again - and for more than the obvious reason. She lies her way to an appearance on an afternoon reality cookery show with Ainsley Harriott, then she blags an audition with Elle Macpherson on Britain's Next Top Model. The script is by Gilhooly and Harry Hill.

Jonathan Ross takes on exuberant comedian and actor Robin Williams this week. It's been a while since Williams has carried a hit film, but his quick wit and improvisational flair should make him the perfect chat-show guest. Model and entrepreneur Elle Macpherson, the new host of Britain's Next Top Model, also joins Ross. Australian musician and comic Tim Minchin completes the line-up.