The group have topped the midweek chart with their latest cut 'Take A Chance On Me', while Rihanna's 'We Found Love' trails in second place.
Labrinth and Tinie Tempah stay firm at three with 'Earthquake' and Professor Green's 'Read All About It' slides from the top spot to four.
Cher Lloyd slips a place to five with Mike Posner hook-up 'With Ur Love' and Pixie Lott is the second-highest new entry with 'What Do You Take Me For?'
Outside the top ten, Loick Essien has landed at 13 with 'Me Without You' and is followed by fellow new entries 'I Need' by Maverick Sabre at 14 and Bruno Mars's 'It Will Rain' at 16.
Tinchy Stryder's new single 'Off The Record' debuts at 22, Nicole Scherzinger's 'Try With Me' tumbles to 27 and Cobra Starship's 'You Make Me Feel...' falls to 31.
Over on the album chart, Susan Boyle is on course to grab her third UK number one album with Someone To Watch Over Me.
Florence + the Machine's Ceremonials sits at number two, while Cher Lloyd's debut Sticks + Stones enters at three.
The Wanted currently reside at four with their second studio LP Battleground and Coldplay's Mylo Xyloto completes the top five.
> View the current singles top 100 here
Watch the music video for JLS' 'Take A Chance On Me' below: