The American duo notch up a third week in the top spot, holding Jennifer Lopez's 'On The Floor' at number two. The former chart-topper continues to perform well despite strong competition from Jedward's Eurovision entry 'Lipstick', which climbs 11 to three.
Also climbing into the Top 10 are David Guetta, Flo Rida and Nicki Minaj, whose collaboration 'Where Them Girls At' jumps ten to five. Chris Brown falls three to number six with 'Beautiful People'.
Lady GaGa's 'Judas' rises from 22 to nine, while Born This Way buzz single 'The Edge of Glory' debuts at number ten.
Meanwhile, Adele's 'Set Fire To The Rain' continues to move up the chart, this week progressing a further six spots to 11.
Among the new entries in the chart this week are: Keywest's 'Back Into Your Arms' at number 25, Rihanna's next single 'California King Bed' at 27 and Nicki Minaj's 'Super Bass' at 33.
This week's Top 10 in full:
1. (1) LMFAO: 'Party Rock Anthem'
2. (2) Jennifer Lopez ft. Pitbull: 'On The Floor'
3. (11) Jedward: 'Lipstick'
4. (4) Bruno Mars: 'The Lazy Song'
5. (15) David Guetta ft. Flo Rida and Nicki Minaj: 'Where Them Girls At?'
6. (3) Chris Brown: 'Beautiful People'
7. (7) Adele: 'Someone Like You'
8. (5) Snoop Dogg Vs David Guetta: 'Sweat'
9. (22) Lady GaGa: 'Judas'
10. (*) Lady GaGa: 'The Edge of Glory'
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Watch LMFAO ft. Lauren Bennet and Goonrock's 'Rock Party Anthem' below: