Duffy has been knocked off the top of the album chart, but Estelle has held on to number one in the singles chart.
It's the third week at the top for the British hip-hop star's single American Boy, featuring Kanye West.
Low by Flo Rida featuring T-Pain held on to number two, while The Kooks' Always Where I Need To Be shot straight to number three.
Meanwhile, American rock group REM's first album in four years took Duffy's number one spot in the album chart.
Duffy's single, Mercy, also dropped down the charts to number five, while 4 Minutes by Madonna, featuring Justin Timberlake, slipped back three places to number eight.
Estelle has been number one for three weeks
Leona Lewis's song for Sport Relief, Better In Time, slipped back a place to number seven.
But there was some good news for the singer as her album, Spirit, climbed one place to number three in the album chart.