Gary Barlow, Cheryl Cole, Alesha Dixon, Kimberley Walsh and Ronan Keating are in serious training for a Red Nose Day challenge that is no laughing matter.
The pop stars will be joined by presenters Chris Moyles, Denise Van Outen, Fearne Cotton and Ben Shephard as they attempt to climb the tallest mountain in Africa, Mount Kilimanjaro.
The climbers have an eight-day trek ahead of them to reach the summit which stands 19,340ft above sea level.
They are embarking on the gruelling climb in a bid to raise enough money to buy a million malaria nets as well as raising money for good causes across Africa and the UK.
Fearne said: "It's mad, it's mental, I can't believe I'm doing it."
She said that she had concerns about the "tiny" Cheryl Cole and Kimberley Walsh, as well as her larger fellow Radio One presenter Moyles managing the climb.
The idea is the brainchild of Take That star Gary. She said: "He came up with this ludicrous idea."
The public can sponsor each climber on the official Red Nose Day website. Fern said: "Just sponsor me because Gary can call Mark, Howard and Jason and they're all millionaires. I'm just going to ring my mum and ask her to give me a tenner so I need you to sponsor me."
Comedienne Jo Brand later advised the presenter to "have a sandwich before you go" in a bid to bulk her up before the arduous climb. But Jo added that Chris would have to be "winched up" and "rolled down".
The climb will be followed throughout by a documentary team and there will be live updates from the mountain on BBC Radio One.
Copyright Speakers Corner 2016