The Saturdays have finally achieved a number one.

The girl band's new single 'What About Us' has become their first ever chart-topping song in the UK, after their previous 11 Top Ten hits all failed to reach the top spot.

The group - who have been around since 2008 - told The Official Charts Company: ''We couldn't be more thrilled to be the UK's official new number one with 'What About Us'. Thanks to everyone who has supported us and the single. We love you all. This is your number one too!''

The song - which features rapper Sean Paul - is also the fastest-selling single of 2013 so far, shifting over 114,000 copies in its first week.

The girls were ecstatic last night as they discovered the news live on air at the Radio 1 studios in London, and posted a series of gushing messages on Twitter.

Rochelle Humes enthused: ''Omg. You guys have made this all possible. I cannot believe that we are the official number 1. For once I'm speechless. We did it guys :-)''

Meanwhile, Mollie King added: ''Team Sats I cannot thank you enough! You have made my dreams come true! The little 6 yr old inside me has come out, I'm so emotional!''

The Saturdays - Rochelle, Mollie, Una Healy, Vanessa White and Frankie Sandford - have knocked Justin Timberlake off the top spot after three weeks with 'Mirrors', which sold 40,000 copies less than 'What About Us'.