Sporty Spice Mel C, comedian Jack Dee, actress Chelsee Healey, television host Dara O'Briain, Radio 1 DJ Greg James and world champion triple jumper Philips Idowu face the toughest Comic Relief challenge to date. They spend five days taking on one of Africa's mightiest rivers, the Zambezi.

Daunting, testing and genuinely dangerous this challenge will see the celebrities face raging rapids, crocodile-infested waters, near-death experiences, emotional school visits and marauding hippos as they go through 'Hell and High Water'. The six celebrities face some of their darkest moments and share their heart wrenching experience, all to raise funds to help educate some of the poorest children on the planet.

7.00 - 8.00:
Lenny Henry kicks off the biggest night in television, this year celebrating 25 years on our screens. Dermot O'Leary and Claudia Winkleman join him to present a first hour absolutely stuffed with contributions from the best comedy and entertainment talent in the UK. Jessie J shaves her head live in the studio, One Direction perform their smash hit Comic Relief single, Miranda Hart stars in a unique (or in her words, 'ruined') edition of Call the Midwife, and Miss Piggy graces us with her presence in the studio.

8.00 - 9.30:
Michael McIntyre and Rob Brydon take over the reins. Highlights include the culmination of another special Comic Relief storyline in EastEnders, Lenny Henry meets the surviving celebrities from this year's extraordinary Zambezi River challenge, Jack Whitehall and Micky Flanagan 'cook off' for Dame Edna Everage in MasterChef, Peter Kay presents the results of his very own physical challenge - something to match anything achieved for the charity by the Zambezi team.

9.30 - 10.30:
John Bishop and Davina McCall pick up the presenting baton as the excitement builds towards one of the most hotly anticipated comic events of the night: Ricky Gervais in a cheap suit - David Brent is back on the BBC. Other key highlights running up to the news are a Comic Relief first from the new queen of comedy Mrs Brown, whilst in the studio Miranda Hart comples the final leg of 'Miranda's Mad March' around the country, joined live by Dawn French and Jennifer Saunders.