Paul McCartney has been popping up all over lately, and many times it has been with pop artists. He's singing on a new song called "FourFiveSeconds" with Rihanna and Kanye West, and it's making the rounds on pop radio.

And did you hear who he collaborated with at the 'Saturday Night Live' after party over the weekend?

Sir Paul played guitar with Taylor Swift as she sang "Shake it Off," and he even sang a few bars of the song, although you can't really hear his vocals very well. A guy named DJ Cassidy posted the clip on Instagram and you can see it HERE.

The Beatles got their start in 1960, and Taylor Swift was was born in 1989. Head exploding? Paul McCartney is 72 and Taylor Swift is 25.

Paul McCartney is back on the Billboard charts thanks to the pop collaborations, and that's after a 29 year gap without a Billboard hit. In other words, he's still got it!