In one clip, Letterman moves towards Jennifer Aniston's face with his tongue out and puts her hair in his mouth.
The TV star revealed that stunning images of Jennifer Lopez and Jennifer Aniston have made her feel insecure.
Although not all were well-known when they appeared in the smash hit sitcom, they all went on to stellar Hollywood careers... but can you name them?
Jennifer Aniston has urged her fans to not vote for Kanye West in the US presidential election, saying doing so is 'not funny'
Jennifer Aniston, 51, took to social media on Sunday to show off her new rescue dog, Lord Chesterfield.
Aniston was joined by her friends and former co-stars as Emmys host Jimmy Kimmel checked in on her.
The actor revealed that the reunion, which was delayed due to the coronavirus in May, might finally be happening.
The actor has said the prospect of bringing in a live studio audience amid the coronavirus is difficult.
"I believe they will always remain friends," she said of the exes who publicly reunited at the SAG Awards in January, "because they're two very special people that can get through anything."
The 51-year-old actress said of her future, ' I see the ocean, I hear laughter, I see kids running'.
The 'Once Upon A Time... in Hollywood' star isn't fussed about hearing what people are speculating about.