Watch Justin Timberlake, Jimmy Fallon's Rap Tribute On SNL 40

The two stars' opening act was crashed by one of the most prominent SNL characters of all-time.

jimmy fallon justin timberlake

Justin Timberlake and Jimmy Fallon have performed several memorable musicals during their guest appearances on NBC's Saturday Night Live, so it made sense that the two joined forces again to open the show's 40th anniversary show.

The two combined to deliver a rap duet that paid homage to SNL's many famous characters and cast members who have entertained the audiences for the past 40 years.

Their rhymes were funny on their own, but their opening act became even funnier when SNL's legendary character Mary Katherine Gallagher (played by Molly Shannon) came out of nowhere. It goes without saying that hilarity ensued.

The video of their opening act can be seen above.