"Katy is a superstar for a reason," John said on the morning show. "That's the thing about working with somebody you love. You get to see them. I had to (make) a video in order to get to see my girlfriend."
Aww, we adore these love birds!
How would you rate their live performance? Tell toofab in the comment section below, and check out all of John's famous exes in the gallery above!