Pharrell Williams has usurped Katy Perry at the top of the US Billboard Hot 100 chart.

The singer's track 'Happy' has been sitting at No.2 on the singles chart for two weeks as a result of the dominance of Perry's 'Dark Horse'.

However, the 'G I R L' star has now reached No.1 after 'Dark Horse' slipped to No.2.

At No.3 on this week's US singles chart is Jason Derulo and 2 Chainz' 'Talk Dirty', whilst John Legend's 'All of Me' is up seven places to No.4.

Beyoncé's 'Drunk In Love' stays put at No.5 and Bastille's 'Pompeii' rises two places to No.6.

Lorde's 'Team' meanwhile has jumped two places to No.7 as her smash hit 'Royals' finally takes a back seat.