Adele's 21 has become the first album to sell over three million copies digitally.

Released in 2011, the album topped America's end-of-year sales charts that year and the following year (12) and it was the 21st bestseller in 2013. It also became the 21st album to sell more than 10 million copies in the U.S.

The Someone Like You singer and her producer Paul Epworth are reportedly at work on the album's follow-up after Adele took time away from the spotlight to become a mum.