The band are to bid adieu to fans in a 'Thank You & Goodnight' tour.
Ronan Keating, Keith Duffy, Mikey Graham and Shane Lynch are to reunite one final time.
The band announced that after twenty-five years together, they are to "go out on a real high."
The album, 'Thank You & Goodnight' is due for release in November will have twelve new tracks including 'I Can Dream' - a tribute to the late Stephen Gately.
The re-worked song will sample a demo of Gately's from 2002 to commemorate the late singer who died of pulmonary oedema in 2009.
The band announced their final comeback in a statement: "When we started out as five young Dublin Northsiders, eager to face the world, we never imagined that we'd still have an army of fans some twenty-five years later...
"If you'd seen our famous first TV appearance on The Late Late Show, you'd probably be surprised too!"
The band thanked their fans for their support over 25 years: "We've played stadiums and arenas all over the world, released six albums, and had almost two-dozen hits. We really can't put into words just how much you, the fans, have supported us along the way."
The boyband also said that the death of Gately would never be forgotten: "The loss of Stephen left scars that we will carry as a band forever."
"We were immensely touched by all the tributes and messages of support that helped us through the dark days. Stephen was our brother and will always be at the very the heart of Boyzone," they added.
The band will play Belfast's SSE Arena on Jan 23, 2019, and Dublin's 3 Arena on Jan 24, 2019.
For a full list of the band's tour dates, click here.