Richard Madeley was called out by Who Wants To Be A Millionaire? host Jeremy Clarkson on Sunday, as he took part as a contestant for charity.
The Good Morning Britain host accidentally called Jeremy the wrong name during his first round, having already made a separate blunder when he entered the studio.
Richard went to sit down in host Jeremy's seat instead of the seat that the guests normally take.
Shortly after, as Jeremy asked the first few questions in round one, Richard made a second blunder that left viewers at home in hysterics.
Jeremy had asked: "Which of these abbreviations is used when someone wants something done immediately?"
He then read out the four options and left it up to Richard to reveal his chosen answer.
It's then that the TV presenter got Jeremy mixed up with former Millionaire host Chris Tarrant, and called him this name instead.
He replied: "I shall answer 'As Soon As Possible', Chris, it's 'A'. Final answer."
Jeremy very bluntly replied: "I'm not Chris," leading to laughter erupting in the audience.
Richard realised his mistake and laughed it off, before asking: "Does that happen [often]," with Jeremy telling him: "You look young but you're senile."
The pair then began chuckling, with Jeremy saying: "This is gonna be great this show," with Richard telling him: "It's going well."
Jeremy then impersonated his "predecessor" when asking Richard for his final answer, once again sparking chuckles from the studio crowd.
Richard later added that his wife Judy Finnigan had warned him before he appeared on the programme not to call Jeremy by Chris' name.
The husband and wife duo had in fact appeared on the series back in 2004, when Chris hosted the show.
Richard spilled: "The last thing that Judy said to me before I came on was whatever you do, don't call him Chris."
Jeremy then got his own back on the guest, replying: "Anyway, Piers," pretending to mix him up with former GMB host Piers Morgan.
Who Wants To Be A Millionaire? continues next Sunday at 9pm on ITV and ITV Hub.
