Greg vowed the 2018 Pedal To The Peaks endurance test would be his last.
But he’s changed his mind and will set off for his cycling challenge from Weymouth, Dorset, during his breakfast show on 13 March.
He’ll then ride through England and Wales – passing through villages, towns and cities – before ending at the finish line in Edinburgh on Red Nose Day on 20 March.
“I do think it will be a ludicrous challenge, and one that I don’t know whether or not I can do,” he says.
“But I’m going to try it.
“A little bit of pain is worth the overall goal of raising loads of money for Comic Relief.”