Taylor Swift Caught Shaking It Off With Sir Paul McCartney

First, he appeared on a new single with Rihanna and Kanye West. Now Sir Paul McCartney is shaking it off with Taylor Swift! Taylor Swift and Paul McCartney were caught in the act during an after-party celebration in honor of Saturday Night Live's 40th anniversary. Taylor was performing for the event when Paul McCartney joined her on stage while she was playing "Shake It Off."

TMZ cameras were rolling and caught the fun!

The fun didn't end there, though. Taylor ended up singing along with the famous Beatle on their song "Saw Her Standing There" while Jimmy Fallon joined in on vocals!