The 43-year-old presenter had just guessed that a video on the gameshow was of Denise Richards’ house.
However, Good Morning Britain host Ben was stunned to see a black toilet in the bathroom.
Taken aback, the TV host then asked what was dubbed “the weirdest question” that Jonathan Ross had ever heard.
Ben said: “A black toilet Denise. I was very taken with it. You have a toilet that’s black?
“Who’s the inspiration behind that? Who’s idea was that?”
Keith Lemon, played by Leigh Francis, jibed: “What’s the inspiration for a black toilet?
“What kind of question is that?”
As the audience laughed, Ben said: “Yeah! I’ve never seen a black toilet before!”
Jonathan Ross then gasped: “That’s the weirdest question I’ve ever heard anyone ask.”
He continued to mock: “Yeah, the cr**per. Why is the c**per black?”
Denise then explained: “Well the bathroom’s all black.
“So I didn’t want to put a white cr**per in there, I put a black cr**per in there.”
Jonathan replied: “Quite right, quite right, quite right. Good answer!”
Through the Keyhole continues next Saturday on ITV at 9.30pm.