The track ends Gotye and Kimbra's four-week consecutive reign at the top spot, with 'Somebody That I Used to Know' falling to this week's third position.
Sean Paul returned to the singles chart with 'She Doesn't Mind' landing in second place, while Labrinth went straight in at four with 'Last Time'.
JLS's Sport Relief charity single 'Proud' gave them another UK Top 10 hit at six, while You Me at Six scored a new entry at 23 with 'The Swarm'.
Nicki Minaj dropped three places from last week's runner-up spot to number five with 'Starships', and Alexandra Burke tumbled nine places from three to this week's number 12 with 'Elephant'.
Florence + the Machine achieved this week's biggest climber, with 'Shake It Out' returning to the top 40 at 35, with a climb of 52 places.
Azealia Banks reached a new peak with '212', which climbed four places to this week's 20 position.
Source: Official Charts Company
> This week's albums chart
Watch the video for Katy Perry's 'Part of Me' below: