Donnie Wahlberg, flanked by his bandmates and surrounded by screaming fans who braved rain to catch a glimpse of them outside the "Today" show studio, said the group had been recording music together since August.
"Really it was the music that brought us back," Wahlberg said on the morning television program.
He said the new album will feature all new material and a concert tour is being planned to start in the fall.
The 1990s-era pop group is also slated to perform in concert May 16 as part of the "Today" summer concert lineup. The concert will be the group's first since it split up in 1994.