For the first time in six years, all five Backstreet Boys – Nick Carter, Brian Littrell, Howie Dorough, A.J. McLean, Kevin Richardson – reunited professionally, for Friday's Good Morning America Summer Concert series in New York's Central Park.
Band member Richardson, 40, who recently rejoined the group three months ago after quitting in 2006, told the legions of cheering fans, "I'm a person that follows my heart and gut, and my heart said this is the time."
Their opening number was "Incomplete." Afterward, the show's news anchor, Josh Elliott, referring to absent co-host Robin Roberts – who on Thursday both departed the show to begin medical treatments and lost her 88-year-old mother, Lucimarian – said, "Robin, that one was for you."
The quintet also sang "I Want It That Way" and "Everybody (Backstreet's Back)."
Despite having sold 130 million albums worldwide, the band is not without its heartaches. In February, Carter, 32, lost his sister Leslie Carter, 25, from an apparent overdose.
In July 2011, McLean, 34, checked into rehab "for personal reasons," he told PEOPLE. "I want to be healthy and perform and sing for people at my very best and happiest."
Things continue to look up for the band, who have two new Backstreet babies on the way – McLean expects a daughter in November, while Dorough will welcome his second son in February.
Band members are currently working on a new album to be released next spring to coincide with their 20th anniversary together.