The pair's collaboration 'Scream & Shout' stays put at number one, while Rihanna advances to two with 'Stay'.
Avicii and Nicky Romero land at three with their new track 'I Could Be The One', Lumineers slips to four with 'Ho Hey' and Bingo Players are up to five with 'Get Up (Rattle)'.
Macklemore and Ryan Lewis climb to nine with 'Thrift Shop', Alicia Keys jumps from 43 to 22 with 'Girl on Fire' and Justin Timberlake slides to 24 with 'Suit & Tie'.
Further down, Bruno Mars vaults from 83 to 31 with 'When I Was Your Man', Rita Ora is at 40 with 'Radioactive', and Example's 'Perfect Replacement' starts at 58.
This week's Irish Top 10 is as follows:
1. (1) will.i.am ft. Britney Spears: 'Scream & Shout'
2. (3) Rihanna ft. Mikky Ekko: 'Stay'
3. (-) Avicii vs Nicky Romero: 'I Could Be The One'
4. (3) The Lumineers: 'Ho Hey'
5. (8) Bingo Players ft. Far east Movement: 'Get Up (Rattle)'
6. (6) Emeli Sandé: 'Clown'
7. (5) Taylor Swift: 'I Knew You Were Trouble'
8. (4) James Arthur: 'Impossible'
9. (13) Macklemore and Ryan Lewis: 'Thrift Shop'
10. (7) One Direction: 'Kiss You'
Watch the music video for will.i.am and Britney Spears's 'Scream & Shout' below: