Greg James has revealed he took the opportunity of rowing along the Zambezi river with Mel C to duet with her.
The Radio 1 DJ and the Spice Girl were among the celebrities who braved hippos, crocodiles and snakes for the challenge to help raise money for Comic Relief, and Greg channelled his inner Bryan Adams and seized the chance to duet with Sporty Spice.
He said: "I was in a boat with Mel C, and to make her feel at home I sang a few Spice Girls songs to her, including that brilliant Bryan Adams one that she did. The duet, When You're Gone, which is an absolute tune. So I was Bryan Adams and she was obviously Mel C. So we had a few moments.
"I think that was because we were a bit sun stroke-y, a bit delirious, and I started singing Spice Up Your Life."
Also on the Hell Or High Water charity trek were comedians Dara O'Briain and Jack Dee, athlete Phillips Idowu and former Waterloo Road star Chelsee Healey, who surprised them all with her effort.
Greg said: "Everyone thought Chelsee was going to be a nightmare! But she's amazing! She is so funny and honest, and what you see is what you get with her.
"She kept everyone going, the morale was kept going because of her, because when we were tired, she would ask a stupid question like, 'Is there a Loch Ness Monster in the Zambezi?'
"She was there with her fake nails and her fake eyelashes, and we had a little game of 'How many are going to be left by the end of the week.' And I think there were four left, which is pretty impressive considering everything we did."
The challenge will air on BBC One on Thursday March 14, ahead of Red Nose Day on Friday March 15.