Katy Perry has bagged the US No.1 single for the second week running.

The pop star's latest track 'Roar' hit the top spot on the Billboard Hot 100 last week and now she has repeated the feat.

She was boosted by the arrival of the track's video, with her streaming count undergoing a 122% increase to 12 million U.S. streams over the week, according to Billboard.

'Roar' is Perry's eighth No.1 in the US, following on from the likes of 'I Kissed a Girl' and 'Firework'.

She is also on course to bag a second week at the top of the UK singles chart too when the final update is released on Sunday (September 15).