Girls Aloud are a British-Irish pop girl group formed through the ITV talent show Popstars: The Rivals in 2002. The group's original line-up comprised Cheryl, Nadine Coyle, Sarah Harding, Nicola Roberts and Kimberley Walsh. They achieved immediate success with their debut single, "Sound of the Underground", which became the 2002 UK Christmas number one. Girls Aloud subsequently became one of the most commercially successful British girl group of the 21st century, achieving twenty consecutive top ten singles on the UK singles chart, including four number ones, and two number one albums.