Harry Styles is so hot right now!
Oh, and did we mention that they played for over 20 minutes?!
Ch-ch-check it out (below) to relive the midnight memories!
Despite both being chart toppers, it looks like both may claim to be the biggest female artist of the year for different reasons.
According to Nielsen Entertainment and Billboard's mid-year report, Beyoncé's self-titled album is the number one selling female album of the year, only being beaten by Frozen's soundtrack!
However, if you added up the individual tracks sold by Katy, with every ten tracks equaling an album, Prism is the highest selling album courtesy of a female soloist this year!