Dermot claimed the ITV favourite decided to make an early exit during the recording because it was taking too long.
The 46-year-old spilled all the details to Jay Rayner on his Out To Lunch podcast this week, where he revealed Eamonn upped and left.
“I did the Mo Gilligan show a while back, to promote X Factor, and Mo’s this charming young guy, comedian on Channel 4, who’s getting this new show,” he explained.
“Eamonn Holmes was with us, and the recording is quite long, and Eamonn, just, sort of, about three quarters of the way through went, ‘I’ve got to be up in the morning, I’m not having this,’ and he just wasn’t there when we came back.”
He continued: “Yes, he just went, but, I mean, he said, ‘How much longer is this going to go on for?’
“I said, ‘Well, I think it’s the third or fourth part now,’ he said, ‘Oh, no. No, no,’ and he just, and it wasn’t announced, it was just literally, like, he wasn’t on the couch.”
This Morning airs weekdays on ITV from 10.30am.