CBS is expanding the Blue Bloods universe with its Boston Blue spinoff - but who makes up the cast? Blue Bloods, which premiered in 2010, followed the lives of the Reagan family, many of whom worked for the NYPD under the leadership of NYC police commissioner Frank Reagan (Tom Selleck).

The Blue Bloods spinoff, Boston Blue, is slowly unveiling its cast for the premiere season. Fans already know the story will continue with Donnie Wahlberg's character, Danny Reagan, as he shifts his career from the New York City Police Department to Boston.