Nick Grimshaw, Jessica Ennis-Hill and Eddie Izzard are among the celebrities to send their support to Greg James after he took a fall on his bike on the fourth day of his Sport Relief challenge.

Radio 1 DJ Greg has been attempting the Gregathlon – five triathlons in five days – but saw himself fall foul of stiff muscles and the biting cold as he lost his balance on his bike at the beginning of the Sheffield leg.

Luckily Greg was unhurt in the incident, but captioned the picture, “Not an ideal start to the Sheffield cycle. My minnnnndds telling me yes, but my body, my body’s telling me NO.”

His cycle will be followed by a run through Sheffield City Centre, where he’ll be joined by fellow Radio 1 DJ Grimshaw, and an indoor swim with DJ Example by his side.

Greg, who is pushing through on four hours sleep a night, said: “Even though my body is saying ‘please stop’, there is no way I’m giving in. I’m in the zone, even if my legs are not. I think they might still be in Belfast. I’m hanging on by a thread. I really need everyone’s help and support to get through the next two days.”

Grimmy led the friends and fans sending their support to the fatigued star and calling on Twitter to donate.

As of Thursday morning, Greg had raised a total of £308,940, which will hopefully spread some warmth to his freezing muscles.

The DJ has suffered for the cause as he had to be pulled out of icy water in Glasgow on Wednesday as he struggled to move.

He finishes the challenge in Norwich on Friday.