In recent months, Corden has been called "difficult and obnoxious" by colleagues and he was also forced to apologise after being banned from the restaurant Balthazar after being "extremely nasty" to waiters.
But Lamb defended the comedian and broadcaster and called him a "good lad".
The former EastEnders actor praised the atmosphere on the set of Gavin and Stacey: "I’ll tell you the way that Gavin & Stacey evolved, it was very definitely a family thing.
"Ruth [Jones] and James created it. But the dynamic is such that if anybody started chucking their weight about during the course of making that they would get very short shrift from everybody."
He added: "It didn’t work like that. So whatever has been said about James, outside of what I’ve experienced in working with him that may be the case. I don’t know."
Corden was also recently criticised by Mel B who called him one of the "biggest d***heads" in showbusiness.
The Spice Girl then said of him: "I think you always have to be nice to the people that you work with whether it be production, camera guys, sound, lighting – we all work for the same thing. So, you should always be nice and he hasn’t been very nice."
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Corden has never addressed any of his alleged behaviour while working but did apologise after being banned from prominent New York restaurant Balthazar for being rude to waiters and demanding free drinks.
Discussing the incident on his late night talk show, Corden said: "It was wrong. It was an unnecessary comment, it was ungracious to the server."
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