Watch 'Friends' Stars Jennifer Aniston and Lisa Kudrow Have Live Curse Off

— -- "I'll be there for you!" goes the "Friends" theme song.

Well, maybe until two of the show's stars start cursing each other out.

Jennifer Aniston and Lisa Kudrow went on "Jimmy Kimmel Live" last night and literally had a Celebrity Curse Off.

"Tonight, the bleeping will be necessary," Kimmel said.

The rules were you could only use each word once. Aniston, 45, began and her first word was a goodie. She even brought in a Greek curse later on. Kudrow, 51, was also on her game and had the advantage of having a teenage son.

After almost three minutes of cursing, watch the video to find out who won! It got "f---ing" real!