Amanda Buffamonteezi was Monica and Phoebe's old roommate before Chandler lived in the building. She was portrayed by Jennifer Coolidge.
Background
Amanda is Phoebe and Monica's old roommate, she appeared in "The One With Ross' Tan", when she comes to visit the two from England. Though she is a New Yorker (from Yonkers), she has attempted to pick up an English accent (but quite often fails, sounding awful in the process - for example saying "I feel like a perfect arse"). She is somewhat egocentric, but in spite of her annoying nature, when she calls Monica's apartment and, after Chandler takes the call and bemuses Amanda by revealing to her that he takes pedicures before handing the phone to Monica, she and Phoebe agree to meet up with her in the coffee shop so as not to hurt her feelings. There, Amanda inadvertently lets out that Phoebe wanted to cut Monica out of her life in 1992 (before the series started) as Monica was at the time driving Phoebe mad by being, as Phoebe later puts it, "controlling, and compulsive, and shrill". Monica is upset about this, but Phoebe explains to her how she's glad now that she changed her mind after realizing what a nice person Monica really was despite all of this. The two make up.
Trivia
The actress Jennifer Coolidge had a main recurring role as Bobbie Morganstern in the Joey spinoff.