TV presenter Davina McCall had to be carried out of the water after completing a 1.5 mile (2.4km) swim in a freezing cold Windermere as part of her Sport Relief challenge.
The presenter appeared to be limp as her team carried her to a nearby hotel.
She had been in tears before the swim, telling BBC One’s Breakfast: “I’m quite nervous about it because I know it’s life-threatening, really, that water.”
“The moment I got in the water my chest felt crushed,” added McCall, 46, after recovering from her ordeal. “I couldn’t do front crawl, I couldn’t put my head under water, I couldn’t breathe.”
“I kept trying to lift my arm to swim, trying to pull the crawl out of the bag, but I couldn’t even get it up. I ended up doing doggy paddle!