Dara O'Briain, Melanie C, Jack Dee, Chelsee Healey, Phillips Idowu and Greg James have been revealed as the six celebrities taking part in a Hell and High Water challenge as part of this year's Red Nose Day fundraising.
The six celebs' BT Red Nose Challenge will be a five-day ordeal, which will see them attempt to navigate their way down the Zambezi river by themselves.
Previous BT Red Nose Challenges have included Gary Barlow leading Chris Moyles, Kimberley Walsh, Cheryl Cole, Ronan Keating, Denise Van Outen, Alesha Dixon, Fearne Cotton and Ben Shephard up Kilimanjaro in 2009.
Sport Relief challenges have included David Walliams taking on a Thames swimming task and comic John Bishop's Week of Hell fundraiser in 2012.
This year's task features the celebs attempting to travel along the deadly 111km of the Zambezi.
O'Briain and co will have to battle against torrential downpours and negotiate rapids officially known as 'Gnashing Jaws of Death', 'The Washing Machine' and 'Oblivion' as they make their way towards Victoria Falls.
"When I was first asked to do this challenge, I did a quick Google search of Zambezi rafting but after the tenth page of people being instantly flung into the water I turned off the computer," said O'Briain.
"But lives can be changed if people put their hands in their pockets in exchange for our misery so that sounds like a fair deal."
The stars will have to live without five star luxury and watch out for crocodiles, lethal snakes and hippos along the route.
They will have to camp on clifftops and soggy riverbanks and deal with 30 degree heat as they take on the river.
Red Nose Day are hoping to raise £1 million with the challenge, which will help children in Zambia go to school.
Fundraising details and donations can be made at rednoseday.com/zambezi.
2013 marks the 25th anniversary of Red Nose Day, which has raised over £600 million for people in the UK and Africa.
