CBS has officially greenlit Boston Blue, a Blue Bloods spin-off centered on Donnie Wahlberg’s character, Danny Reagan, and his son Sean. However, longtime fans may be surprised to learn that Andrew Terraciano, who played Sean Reagan across all 14 seasons of the original series, won’t be reprising the role.

Although “Boston Blue” is a direct offshoot of “Blue Bloods,” the Reagan family will look a bit different this time around. Mika Amonsen has joined the CBS drama in a series regular role playing the youngest son of Donnie Wahlberg's character,