"There's a story about the famous scene that very few people know about and I'm not sure I should …," he began, warning Barrymore that not even she knew what he was about to say.
"So we embrace and we start kissing, and you really kissed me. I mean, you really kissed me. I was not ready for it in the least and I'm a man, I was a very young man back then, and I had, uh, feelings."
As Vartan continued, Barrymore was left in no doubt as to what exactly he meant by "feelings".
"The feelings … they just happened, and I very quickly realised I was in a very bad spot because I was wearing very loose slacks and I thought, 'This is going to be a disaster when they cut, I must pre-emptively end this,' " he continued.
"So what I did, in a panic, I just yelled cut, and bent over and said, 'Oh guys, sorry, I put my back out playing ball.' … Anyway, I went off into my corner and … finally I was able to compose myself, and luckily the subsequent scenes went on without a hitch, but that was, uh … You're a very good kisser."
Barrymore took the confession in good humour, revealing that she did indeed remember "going for it" with the kiss because she knew Vartan was single at the time "so I wasn't going to offend anybody".
Earlier in the segment, Vartan was overcome with emotion when he spoke about the impact the film had on his life.
"This movie has been a huge part of my life. Every time I'm stopped, it's always Never Been Kissed. That's a pretty amazing thing to be a part of, and this reunion is just wonderful," he said.
Watch the full clip below:
