Richardson leaves Backstreet Boys

Singer Kevin Richardson is to leave boyband the Backstreet Boys to pursue other interests.

In a message to fans on the band's website he said it had been a "tough decision for me".

"It was necessary in order to move on with the next chapter of my life," the singer added.

The group formed in the late 1990s and have sold more than 35 million albums. They spent four years apart from 2001 when AJ McLean went into rehab.

They reunited in 2005 to release the album Never Gone.

The remaining members, McLean, Nick Carter, Howie Dorough, and Brian Littrell, said they had no plans to replace Richardson.

"The door will always be open for him to return to the Backstreet Boys. We wish him the all the best in his future endeavors," they said on the band's website.

The group plans to return to the studio to begin work on their next album, which is due later this year.