Comedian John Bishop started to feel delirious as sleep deprivation left him barely able to speak during his mammoth triathlon challenge.
The funnyman has been battling to row across the English Channel on just one hour's sleep following a gruelling 185-mile bike ride.
The comic was barely able to talk coherently during a live interview with Radio 1, with fellow rower Davina McCall having to step in.
Organisers of the "week of hell" BT Sport Relief Challenge said he was "starting to feel delirious". He is travelling from Paris to London in five days using a bike and rowing, then finishing off by running three marathons on consecutive days.
Bishop - who is joined on the rowing stint by Denise Lewis and Freddie Flintoff, together with McCall - has also had to contend with choppy seas which have slowed their progress. The team managed just five miles in two hours at the start of their crossing of the world's busiest seaway and is around three hours behind schedule.
Bishop, 45, is already nursing aches and pains from the Paris to Calais cycle ride. The saddle-sore star had muscle damage and severe bruising on his bottom from the punishing 18 and a half hours of pedalling.
He said: "I massively underestimated how tough the cycle would be - there were 10 hours yesterday when I didn't say a word to anyone, it was that fierce. If I had come across a phone box, I would have got in it and just called my mum."
Their efforts have already raised more than £366,000 for the BT Sport Relief Challenge. The aim is to raise enough money to vaccinate 250,000 children in Africa, as well as help with projects in the UK.
If he manages to keep going, Bishop is expected to make it to Trafalgar Square in London on Friday.
The team finally reached Dover after completing the rowing leg of the challenge in seven hours and 45 minutes.