20 Mind-Blowing Facts About It's Always Sunny In Philadelphia

8. Danny DeVito's Kids Convinced Him To Join The Show

The star that McElhenney thought would be a perfect fit for the show was Danny DeVito and the two met to discuss the proposed character at DeVito's home. Although the character was just an idea and Rob was winging it with his answers to DeVito's questions, the star looked interested. But the main factor in DeVito signing on was the fact that his children were huge fans of the show and basically told him in no uncertain terms that he had to join. After DeVito agreed to play Dennis and Sweet Dee's father Frank Reynold's it was all systems go and the show has went from strength to strength since then.