Mika Amonsen will replace Andrew Terraciano, who played Sean Reagan throughout the 14-season run of "Blue Bloods."

Mika Amonsen ( Thanksgiving) has joined the show’s cast as Sean Reagan, the youngest son of series lead Donnie Wahlberg’s character, Danny Reagan. Amonsen will take over the role played by Andrew Terraciano throughout Blue Bloods’ 14-season run on CBS.

As for Amonsen, he has previously starred in an episode of Apple TV+'s Pachinko, Suits and Designated Survivor, as well as 2023 slasher Thanksgiving. The original series saw the role of Sean played by Terraciano, with the other Reagan son, Jack, being played by Andrew's real-life brother Tony.