With Mark Watson and Professor Brian Cox

Comedian Mark Watson swings by the studio to chat about his record-breaking stand-up for Comic Relief.

Despite vowing never to do another after his Last Ever 24 Hour Show at the 2009 Edinburgh Fringe, this year's will be slightly longer, lasting an hour for every one of Comic Relief's 25 years, and will start at 11pm on 28 February at the Pleasance Theatre in Islington, lasting until the following midnight!

There will also be a special show announcement about the 6 Music Breakfast show and Red Nose Day. Very exciting!

Wednesday also sees Professor Brian Cox on the show for his weekly science chat.

Brian is a TV presenter, professor, particle physicist and Royal Society University Research Fellow who is currently working at CERN. He's also in charge of single-handedly making science cool.

Shaun, on the other hand, is in charge of pure silliness and a soundtrack of superb tracks, both old and new, to help you kick out the jams!