Saturday Night Live celebrated 40 years on NBC on Sunday night. One of the guests on the show was Taylor Swift. At the after party she teamed up with Paul McCartney on the bass, and Jimmy Fallon on stage to sing "Shake It Off."

McCartney played the bass and tries to sing along with Swift while Jimmy Fallon went crazy on stage.

On the special that aired on NBC, Taylor played the role of Allison during “The Californians” sketch. The sketch also starred Bradley Cooper, Betty White, Bill Hader and more. The highlight of that sketch was White and Cooper making out on stage! Also, the ending with David Spade.