Girls Aloud's comeback single Something New has been beaten to the UK number one spot by Olly Murs' latest release.
Something New is the group's first single for three years and is also the official Children In Need single.
It has entered the chart at number two, behind Olly Murs' Troublemaker, which has become the former X Factor contestant's fourth number one.
Last week's number one, Little Things by One Direction, has dropped to third, the Official Charts Company said.
Emeli Sande's collaboration with Labrinth, Beneath You're Beautiful, is at four, with Alicia Keys scoring a new entry at number five with Girl On Fire.
And veteran rock band AC/DC have two entries in the top 40 this week after making their back catalogue available on iTunes for the first time. Back In Black, originally released in 1981, is at number 27, with Highway To Hell at 40.
Meanwhile, Rihanna has gone straight to the top of the album chart with Unapologetic, which has become her third number one album in three years.
Madonna, Norah Jones and Eva Cassidy are the only other female artists to have had three chart-topping albums in a row.
One Direction have slipped to number two with Take Me Home, and last year's X Factor winners Little Mix have a new entry at number three with their debut DNA.
The most popular album of the past week was Now That's What I Call Music! 83 - but multi-artist compilations do not qualify for the main chart. Now! 83 is the fastest-selling album of the year so far, with 295,000 copies sold in its first week.
It has sold almost twice as many copies in its opening week as the fastest-selling album by a single artist - Babel by Mumford and Sons, which shifted 158,000 copies when it came out in September.