JEFF Brazier has vowed to go on a health kick after his fiancee jokingly called him "chubby".
In an Twitter video, the presenter, 39, also said he'd been spurred into action after his teenage son Bobby called him "corroded" after a football game.
In a Twitter video the presenter said: "I can only respond by getting some new gym gear - thanks you for that for my birthday [to Kate] and to eat vegetarian.
"Only thing you can do to bounce back! I'm on it!"
He then turns to Kate, who works in PR, and asks her if he is "overweight."
To which she replies: "Chubby".
Good-natured Jeff then muses: "Wow. Imagine if this was the other way round and said you're chubby. Anyway."
Jeff, who has a regular spot on This Morning, also has another son, Freddie, 13, with Jade.
He and Jade were married between 2002 and 2004 before she died of terminal ovarian cancer in 2009.
Jeff became engaged to Kate last year and said on Loose Women at the time: "Kate's a wonderful woman.
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"She's got a great relationship with the boys.
"Freddie is hell-bent on having a stepmum, it really means a lot to him.
"There was a lot of pressure on Kate, but she has done a great job."
Meanwhile the presenter revealed that his son told him that he wanted to strip for The Real Full Monty when he was older - like Jeff did - in order to raise awareness for cancer.
Just minutes before Jeff went on stage for the TV show, he said he got a text from his boy that left him "emotionally floored".
Speaking in an Instagram video, Jeff said: "My son put it into perspective for me, telling me he was really proud of me, that I was a ledge for doing it, and that I should tell Ashley [Banjo] that in a few years time, when he's old enough, he wants to do it to carry on his mum's legacy, which absolutely floored me emotionally.
"It turned the performance from performing a routine to something far greater bigger than I ever imagined it would be."
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