HOLLY Willoughby has revealed she broke down in tears "many times" on upcoming show Freeze the Fear.
The presenter, 41, and comedian Lee Mack host the new BBC series with extreme athlete Wim Hof.
It follows eight celebrities including Strictly's Dianne Buswell, rapper Professor Green, singer Alfie Boe and EastEnders actress Tamzin Outhwaite taking part in gruelling challenges set in freezing temperatures and icy water.
Speaking on The One Show tonight, Holly said: "This is not something they get voted off or a popularity contest, they are really challenging their minds and bodies.
"All I can tell you is it was intense for everybody, medics were involved, and I was in tears at many many points throughout it.
"It was kind of life changing, it is amazing, it's one of the best things I've ever done."
Most read in TV
Holly said the show pushed the celebs to their limits, adding: "Lots of them turned up and said, 'I hate the cold.'
"But yeah I'm very proud of that lot. They jump into a frozen lake, it's near freezing, that is their entry point. The first thing they have to do.
"When you hit that cold water it literally takes your breath away. So it's that thing of using your mind to control your fear, it's not normal to jump into a freezing lake."
Extreme athlete Wim Hof will be supervising the celebrities and guiding them through his series of radical challenges.
The group will live together in a tented village in sub-zero temperatures, surrounded by spectacular, icy scenes of Northern Italy.
Under his encouragement, the celebrities will reap the rewards of cold-water therapy and face a unique test of mental strength like no other.
Freeze the Fear with Wim Hof airs in the Spring on BBC One.