Holy shiz! Who knew this song was going to do as well as it is?!
Meanwhile, Adele's Rolling In The Deep hasn't taken too badly a hit, standing strong at number two, while our most beloved Brit Brit's 'Till The World End remix featuring Nicki Minaj and Ke$ha has shot up to the number three spot!
Black Eyed Peas Just Can't Get Enough and Bruno Mars' Lazy Song round out the top five!
1. Katy Perry ft. Kanye West "E.T."
2. Adele "Rolling in the Deep"
3. Britney Spears ft. Nicki Minaj & Ke$ha "Till the World Ends"
4. Black Eyed Peas "Just Can't Get Enough"
5. Bruno Mars "Lazy Song"
6. Rihanna ft. Britney Spears "S&M"
7. J. Lo ft. Pitbull "On the Floor"
8. Ke$ha "Blow"
9. Jeremih ft. 50 Cent "Down On Me"
10. Chris Brown ft. Lil' Wayne & Busta Rhymes "Look At Me Now"