Sarah Nicole Harding (born Sarah Nicole Hardman; 17 November 1981) is an English singer-songwriter, dancer, model, and actress. She rose to fame in late 2002 when she auditioned for the reality television show Popstars: The Rivals on ITV. The programme announced that Harding had won a place as a member of the girl group, Girls Aloud. The group has achieved massive success, having twenty consecutive top ten singles (including four number ones) in the UK, six studio albums have all been certified platinum by the British Phonographic Industry (BPI), two of which went to number one in the UK, and accumulating a total of five BRIT Award nominations. In 2009, Girls Aloud won "Best Single" with their song "The Promise".

During the group's break, Harding turned her attentions to acting, appearing in Bad Day, the BBC television film Freefall, Run for Your Wife, and St. Trinian's 2: The Legend of Fritton's Gold. Harding contributed three solo songs to the soundtrack of St. Trinian's 2. Harding has also modeled for Ultimo lingerie. In 2011, Harding entered a rehab facility for depression, alcohol addiction, and prescription drug abuse. In late 2012, Harding reunited with Girls Aloud to celebrate their tenth anniversary together. In early 2013, they announced that they had split up.