EXCLUSIVE: After a series of tests, Grey Damon (Aquarius), Hamilton’s Okieriete Onaodowan, Danielle Savre (Too Close To Home), and Barrett Doss (Marvel’s Iron Fist) have been cast as series regulars in the upcoming Grey’s Anatomy firefighters spinoff opposite Jaina Lee Ortiz and the mothership series’ Jason George. The 10-episode drama, which follows a group of heroic firefighters, hails from Grey’s Anatomy creator Shonda Rhimes’ Shondaland.

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Set in a Seattle firehouse, the spinoff is being written by Grey’s executive producer/co-showrunner Stacy McKee. From the captain to the newest recruit, the show revolves around the brave men and women who risk their lives and their hearts both in the line of duty and off the clock. All four new cast additions will play firefighters, Lieutenant Jack (Damon), Dean (Onaodowan), Maya (Savre) and Victoria (Doss).

Start of production on the spinoff was pushed back a week or so to finish casting. The lead characters are expected to be introduced in an episode of Grey‘s Anatomy this fall before the offshoot series launches midseason.

McKee executive produces the spinoff with director Paris Barclay and Shondaland’s Rhimes and Betsy Beers for ABC Studios and Shondaland.

Friday Night Lights alum Damon has co-starred on Aquarius, The Nine Lives Of Chloe King, Twisted and Star-Crossed. He plays Mirror Master on The Flash and will be seen in the feature Cadaver. Damon is repped by Paradigm and Thirdhill Entertainment.

Broadway standout Onaodowan originated the roles of Hercules Mulligan and James Madison in the 2015 smash Hamilton. He also took on the role of Pierre in the musical Natasha, Pierre, and the Great Comet of 1812 this past summer, replacing Josh Groban. In TV, he has done arcs on Netflix’s The Get Down and HBO’s Ballers. Onaodowan is repped by Innovative Artists and Red Letter Entertainment.

Savre toplined Tyler Perry’s TLC scripted drama,Too Close to Home. She will next be seen in the feature Deep Blue See 2. Savre is repped by Talentworks and Capstone Talent Management.

Barrett, who plays Megan on Netflix’s Iron Fist, will be seen in the upcoming feature Marshall and was just seen on Broadway in Groundhog Day as Rita. She is repped by Beth Rosner Management and BRSGage.