Chat show host Jeremy Kyle fell to the floor as a guest stormed onto the stage to launch herself at her own sister.
Cameras just missed the moment that he hit the ground, but they caught the host being helped back up to his feet by security.
Following Wednesday's Jeremy Kyle Show, the presenter, 51, tweeted a photo of himself caught face-down on the floor with the caption: "What a show this morning, It's all been going off!"
Kyle was apparently not deliberately knocked over as earlier media reports suggested, but instead was bowled over in surprise.
A spokeswoman for ITV said: "Jeremy was shocked when the guest ran on the stage and fell off the chair."
The woman, named Emma, was confronting her sister in the segment labelled "I'll prove we're not sisters - can you prove you're not on drugs?"
But Kyle did not even have a chance to introduce her to the stage of the ITV show before she came marching on.
The presenter found the funny side and joked: "Just back from a holiday, open my mouth, and get flattened," as the audience laughed.