Monica initially hides under the covers, before popping her head up to cheers from the show’s audience.
Part of the scene - which features the live audience laughing hysterically - has rarely been seen before.
“Here’s one of my favourites. To give a little backstory, Chandler and Monica were supposed to have a one-night fling in London. But because of the audience’s reaction, it became the beginning of their love story,” Cox wrote on Instagram.
“In this scene, before we started rolling, he whispered a funny line for me to say. He often did things like that. He was funny and he was kind.”