During the appearance, the 46-year-old actor and the 52-year-old rocker entertained the crowd with a drum-off. Check out the video below!
Amanda Seyfried also made an appearance on the show, where she promoted her new film A Million Ways to Die in the West, which hits theaters on May 30.
Will Ferrell – ‘Tonight Show Starring Fallon’
FYI: Amanda is wearing Saint Laurent.