Exhausted TV host Christine Bleakley completed her water-ski challenge across the English Channel today - and said it was "utter torture".
The BBC's One Show presenter finished her feat in one hour and 40 minutes and was in tears after she pulled on to dry land in France.
But the arm-aching journey was not without a hitch as the star - who is scared of water - fell in eight times and encountered swell and waves of up to 8ft (2.4m).
Bleakley, who swapped her usual polished glamour for a black head-to-toe wetsuit and red lifejacket, had been repeatedly delayed because of poor weather.
She said: "Halfway through, I thought 'I can't do this' because everything was starting to give. I had searing pain in my lower back, my legs were starting to wobble, and my hands - I just couldn't hold on any longer.
"But I managed to get the strength from somewhere and I can't quite believe I've done it."
Bleakley said even her co-star Adrian Chiles, who had been providing support from the boat accompanying her, had been in tears at the completion of the Sport Relief challenge.
She got the go-ahead to set off from Dover at 7.46am after days of delays due to poor weather.
She had to dodge tankers during the 22-mile route across the world's busiest shipping lane.
And she braved miserable temperatures of just 5C (41F), with a wind chill below freezing.
Bleakley was moved to undertake the challenge - thought to have raised at least a quarter of a million pounds - following a trip to Uganda with Sport Relief in 2008.
The presenter even managed to raise a smile during the challenge but said it was a gruelling ordeal.
She told Radio 5 Live presenter Gabby Logan that it was "tougher" than she had ever imagined.
"There were so many moments when I really did crash and burn. It was just utter torture for a good portion of it."
She said the repeated postponements were "like waiting for an operation".
Bleakley's achievement is all the more remarkable as the presenter is scared of water.
"I had this terrible experience as a little girl. My dad, thankfully, saved my life," she said.
"I think I was in the last throes. I was in a swimming pool on holiday and I went under the water and, as I say, Dad pulled me out and managed to get me back to life again. And I haven't gone near the water ever since.
"I can swim about one length and that's it so I've had to overcome a lot of personal fears.
"It's scary when you're out there and you see 8ft waves alongside you, and the swell that stops your view even from the boat in front of you.
"And there's a huge amount of waves created off the back of the huge ships that go across the Channel too.
"So it was just incredible - it's very difficult to put into words."
Bleakley - who has been through months of training with Professor Greg Whyte - said the effort of hauling herself out of the water after each fall was "exhausting".
To support Bleakley, make a donation at www.sportrelief.com/christine