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

The former "Friends" stars really got creative during their 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.

"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!