After entering 2011 with 'Grenade' at number 1 in the Billboard Hot 100 chart, Bruno Mars has done it again. 

His balladic single is back at the top spot in the USA, pushing Katy Perry's 'Firework' into second place. Mars' track was released in the UK on Monday January 10 and shot to number 1 in the midweek charts. 

Earlier this week he released a string of UK tour dates and a one-off show in London to celebrate the launch of his debut album, 'Doo Wops and Hooligans'. The chart-topping singer/songwriter is also nominated for 7 Grammys. 

Watch Mars' video for 'Grenade' here: