Kevin Richardson is leaving the Backstreet Boys on the eve of the start of work on the group's next album. In a statement on its Web site, the group said Richardson was leaving after 13 years to "purs

Kevin Richardson is leaving the Backstreet Boys on the eve of the start of work on the group's next album. In a statement on its Web site, the group said Richardson was leaving after 13 years to "pursue other interests" and "gave his blessing to continue the music without him."

Richardson will not be replaced in the group, which also features Brian Littrell, Howie Dorough and AJ McLean. "The door will always be open for him to return to the Backstreet Boys," the statement said.

"It was a very tough decision for me but one that was necessary in order to move on with the next chapter of my life," Richardson said, without elaborating on his future plans.

Backstreet Boys are in the studio this weekend beginning the follow-up to 2005's "Never Gone," which debuted at No. 3 on The Billboard 200.