In 2008, Cheryl replaced Sharon Osbourne as a judge for the fifth series of "The X Factor" alongside creator Simon Cowell, Dannii Minogue and Louis Walsh. She was given the girls category (made up of female solo contestants aged 16 to 25) and subsequently ended up as the winning judge when Alexandra Burke was crowned the winner of series five on 13 December. She returned for the sixth series in 2009 and was given the boys category (made up of male solo contestants aged 16 to 25). She was the winning judge for a second consecutive year when Joe McElderry won on 13 December. Cowell referred to her as "one of the best I've ever worked with." Cheryl returned for the seventh series in 2010 and mentored the girls category again. This was the first series in which she was not the winning mentor, when Rebecca Ferguson finished as runner-up to Matt Cardle.