The Late Late Show presenter came under fire in November after a joke from Gervais's Netflix stand-up special was used almost word-for-word in his opening monologue.
Gervais retweeted a video comparing the two jokes, but later removed it to prevent further piling on Corden, who had come under fire just a week before for his behaviour towards staff at New York's Balthazar restaurant.
Speaking on BBC Radio 5 Live's Headliners podcast, Gervais confirmed to presenter Nihal Arthanayake Corden had both publicly and privately apologised to him for the error.
"He did [say sorry]," Gervais said. "I said 'Don’t worry about it'. I said 'if your writers were in the back of the room when I was warming up and you got it out there before I did it on Netflix…'.
"But whatever you think of James Corden, there is no way he knowingly ripped off my joke and thought he’d get away with it."
Gervais added he found the whole incident 'funny' and reacted because he "thought it was absurd that it was such an obvious rip-off".
The Office creator added he believes Corden's error was a genuine mistake, saying a member of his writing team either "stitched him up" or thought it was an original joke, not realising they'd seen it years prior.
"I don’t know how he got to it because the writer must have walked him through and said 'do this' and 'do that'. Or he saw it five years ago and completely forgot about it and thought he’d made it up. That can happen as well," the After Life star argued.
"There are some plagiarists but a lot of it is genuinely accidental. So that is clearly my routine, but I don’t think he came up with it at all. I think a writer pitched that to him and didn’t tell him it was mine, or the writer forgot."
The joke in question appeared in Gervais's 2018 Netflix special Humanity, and compares people getting mad on Twitter to those getting angry at a local town notice board.
Corden said: "I think when you see Elon Musk talk about Twitter, he says, 'well it's the town square', but it isn't.
"Because if someone puts up a poster in a town square that says guitar lessons available, you don't get people in the town square saying, 'I don't want to play the guitar! I want to play the piano, you piece of s***!'
"Well that sign wasn't for you, it was for somebody else, you don't have to get mad about all of it."
After being called out online, Corden put his hands up and admitted the joke was too similar to be pure coincidence, and credited Gervais as he corrected the error.
He responded: "Inadvertently told a brilliant Ricky Gervais joke on the show last night, obviously not knowing it came from him. It’s brilliant, because it’s a Ricky Gervais joke. You can watch all Ricky’s excellent specials on Netflix. Jx"
WATCH: James Corden responds to accusation he stole joke from Ricky Gervais