A.J. McClean of the boy band the Backstreet Boys has entered a rehab center ahead of the group's upcoming summer tour with New Kids on the Block.
The 33-year-old did not specify his ailment. McClean began treatment programs in 2001 and 2002 and has suffered from alcohol abuse, depression and anxiety.
"With 2011 being a busy year for Backstreet, I want to be healthy and at my best," he said. "None of this will affect our current tour plans and I look forward to seeing everyone really soon!"
He said on his Twitter page on January 9: " Its gonna be a great year! I love u all and wish me luck! I start my sober journey tomm!"
The Backstreet Boys consists of A.J. McLean, Howie Dorough, Brian Littrell and Nick Carter. The group, which released songs such as "I Want It That Way" and "I'll Never Break Your Heart", formed around 1992, went on hiatus around 2002 and returned with new music in 2005. Kevin Richardson left the band in 2006.
McClean contacted Richardson on Twitter in September, saying: "Its aj call me bro. Been trying to get together with you so u can meet the wifey and see me of course:)"
Richardson has not updated his Twitter page since December 2009.
The Backstreet Boys and New Kids on the Block performed at the American Music Awards last year to promote their tour, which is set to begin on June 2 in Uncasville, CT.