Sandi Toksvig smashed Krishnan Guru-Murthy's cake in a "soul destroying" moment on "Great Celebrity Bake Off for Stand Up to Cancer".
The Channel 4 newsreader is part of the broadcaster's charity special edition of the baking TV favourite, but he was left mortified when the show's host tried to help him flip his cake between two cooling racks.
In scenes set to air on tonight's episode (02.04.19), the tin slipped through the middle before falling onto the worktop, and it all went downhill from there.
Krishnan is quoted by the Daily Mirror newspaper as saying: "It's very soul destroying ... I don't know whose fault it was. She said it was my fault.
"I didn't feel it was my fault."
The celebrity contestant described the awkward moment as a "disaster" as he explained how it unfolded.
He added: "Sandi got hold of the bottom and she said, "You get hold of the top". And of course it didn't work, because it's very hard to stay in sync with someone else as they turn it over. The whole thing fell apart and collapsed, it was a disaster."
Sandi has gone above and beyond during the charity "Bake Off" series, and last week the co-host stepped in for rapper Big Narstie after he called in sick.
Co-host Noel Fielding - who called his colleague "Little Narstie" - joked it was a "seamless swap".
Explaining the situation, he said: "There has been a development overnight.
"Unfortunately, Big Narstie can't be with us today as he's a little bit unwell, but he will be replaced by another baker. It's a seamless swap, don't worry."
Sandi then admitted she hasn't baked a cake since school, quipping: "I haven't cooked a sponge since domestic science O-level."