While filming "The Whole Nine Yards," Matthew Perry revealed that his co-star Bruce Willis was a bit worried about how the film would be received by audiences. While Willis worried about the fate of the film, Perry was confident that fans would enjoy the movie. So, the two pals made a bet. "Bruce hadn't been sure the film would work at all, and I'd bet him it would — if he lost, he had to do a guest spot on 'Friends.'" Of course, it was Perry who ended up being triumphant in the situation. "Despite the partying, we were all pros on that movie and managed to turn out a huge crowd pleaser," the actor said in his book, revealing exactly why Willis was cast on the popular TV series.

As "The Whole Nine Yards" went on to become the number-one film in the United States for three straight weeks, it was clear that Willis was going to have to pay up. The movie star was eventually cast in the role of Paul, the father of Ross' young college-aged girlfriend, Elizabeth. While Ross dated Elizabeth, Rachel (Jennifer Aniston) found herself drawn to Paul and the two also dated — making things awkward for exes Ross and Rachel.

Willis only appeared in three episodes as Paul. However, his performance was enough to earn him an Emmy award for Outstanding Guest Actor in a Comedy Series.