British fitness guru Joe Wicks has announced that he will attempt to work out for 24 hours for charity - and admitted he could "burst into tears" during the challenge.
The 35-year-old Body Coach is hoping to raise millions after revealing he has signed up for next month's "savage" ordeal.
The BBC Radio 2 Children In Need Challenge will be a "real test of endurance", he said.
"It's going to be tough, I'm not going to sleep, there's no end to it. I've just got to keep going," the virtual PE teacher told the PA news agency.
"It will be draining and I know that when you get true fatigue and you're really exhausted, you get really emotional. I'll probably end up, at some point, bursting into tears."
"But," the star added, "hopefully people will be there to pick me up and say, 'Come on, keep going'."
Wicks has been advised that he should try to consume 10,000 calories during the fundraiser - the same number he will burn.
"Even if you're eating loads of burgers, ice cream and chocolate, to eat 10,000 calories is still . . . very tough", he said.
"But I'm sure we'll make some high calorie drinks, and get some avocado and peanut butter in there and fatten it up.
"Hopefully, I'll have predominantly healthy food but with the odd chocolate bar or packet of fruit gums.
"I want to keep my blood sugar levels stable rather than just smashing the sweets and the chocolate."