GIRLS ALOUD singer SARAH HARDING has stunned fans by announcing she's set to leave the group for a year.The pop star, one fifth of Britain's most commercially successful girl band, will hang up her microphone to concentrate on pursuing an acting career. The news has fuelled persistent reports the pop band is set to part ways, as each of the singers is busy with different ventures. Harding tells Britain's Heat magazine, "It's not fun when it feels like groundhog year. We've been on a treadmill for six years and need a break. "It's very difficult when there are five of you trying to make decisions. Three might vote to do something that you don't want to do - that can be frustrating." The blonde beauty, who has landed a role in the upcoming movie St Trinians 2, insists she doesn't plan to leave the group but admits, "Acting is good for me because I've always been a drama queen."