James Corden has slammed fellow US late night host Bill Maher, who has called for fat-shaming to "make a comeback".
Maher was speaking on his Real Talk programme when he started criticising efforts to de-stigmatise being overweight.
The 63-year-old talk show host said "we have gone to this weird place where fat is good".
Maher, a prominent TV personality in the US, said being fat "isn't a birth defect, no-one comes out of the womb needing two seats on the airplane".
He added: "Fat-shaming doesn't need to end, it needs to make a comeback."
This was enough to provoke anger in the Gavin & Stacey star, who has struggled with his weight throughout his life.
Appearing on his The Late Late Show on Thursday, 41-year-old Corden said Maher was encouraging bullying.
Corden argued fat-shaming "hasn't gone anywhere" and that "we are reminded of it all the time".
Discussing his own efforts to keep the pounds off, Corden said "we're not all as lucky as Bill Maher, we don"t all have a sense of superiority that burns 35,000 calories a day".
The comic actor added: "It's proven that fat-shaming only does one thing - it makes people feel ashamed. And shame leads to depression, anxiety and self-destructive behaviour. Self-destructive behaviour like over-eating.
"Fat-shaming is just bullying and bullying only makes the problem worse."
Corden found plenty of support on social media for his takedown, among them was British actress Jameel Jamil, who has been open about her own struggles with her weight.
She said Corden's monologue was "brilliant", adding: "I recommend it to you all.
"I whole heartedly agree with everything he is saying here and I hope @billmaher takes a second to listen, because this is so important."
Do you have a story to sell? Get in touch with us at [email protected] or call us direct 0207 29 33033.