AJ McLean, a member of the Backstreet Boys, is preparing for a six-week residency at Sphere in Las Vegas to celebrate the 25th anniversary of their album "Millennium." The group will perform the album in its entirety, including some deep cuts that haven't been performed in years. Despite facing challenges with late-night rehearsals and a demanding schedule, McLean is excited about the upcoming show and the opportunity to create new memories with the band. The residency marks a significant milestone for the Backstreet Boys, who are considered a legacy act and are the first pop group to perform at Sphere. The group is also releasing a deluxe reissue of "Millennium" featuring outtakes, live recordings, and a new song called "Hey."