The highest new entry of the week comes from Eric Prydz, the Swedish DJ who topped the charts in 2004 with 'Call On Me', whose new single 'Pjanoo' lands in second position.
Rihanna climbs a place to third with 'Disturbia', while Irish trio The Script fall to fourth with 'The Man Who Can't Be Moved'.
Meanwhile, Scottish rock trio Biffy Clyro continue to make headway on the chart, climbing from ten to five with 'Mountains'.
Notable gains come from New York duo Little Jackie, who jump from 21 to 14 with 'The World' Should Revolve Around Me', and Danish group Alphabeat, who leap from 35 to 15 with 'Boyfriend'.
The top ten in full (click for our reviews):
1. (1) Katy Perry: 'I Kissed A Girl'
2. (-) Eric Prydz: 'Pjanoo'
3. (4) Rihanna: 'Disturbia'
4. (2) The Script: 'The Man Who Can't Be Moved'
5. (10) Biffy Clyro: 'Mountains'
6. (3) Kid Rock: 'All Summer Long'
7. (5) Madcon: 'Beggin'
8. (6) Dizzee Rascal ft. Calvin Harris: 'Dance Wiv Me'
9. (7) The Verve: 'Love Is Noise'
10. (8) Noah & The Whale: '5 Years Time'
> Click here for this week's UK albums chart