Stranger Things Broadway play adds season 5 newcomer, Grey’s Anatomy alum

The Upside Down continues taking over Broadway as the cast for the U.S. version of Stranger Things: The First Shadow continues to grow.

Louis McCartney will reprise his role of young Henry Creel/future Vecna from the London West End production when the show makes its stateside debut in New York next year. But among the new batch of casting unveiled Wednesday is Alex Breaux, who's already playing a mysterious series regular character in Stranger Things season 5, which premieres on Netflix in 2025. Fans only caught a glimpse of him on the show in a behind-the-scenes sneak peek, revealing him in a black militarized uniform holding an automatic rifle.

On stage, Breaux will play the new Dr. Martin Brenner, a role played by Patrick Vaill in the London stage version and Matthew Modine on the Netflix series.

Alex Breaux, T.R. Knight, and more join Broadway's 'Stranger Things: The First Shadow'. Netflix (3)

Stranger Things 5 confirms 1-year time jump, 2025 premiere for final season

Another piece of interesting casting: Grey's Anatomy alum and The Flight Attendant actor T.R. Knight will hit the stage as Victor Creel, Henry's father. Horror icon Robert Englund played the character on the series, while Michael Jibson took the role for the London production.

Also joining the Broadway cast are Alison Jaye (Shameless) as young Joyce Maldonado, Burke Swanson (Back to the Future: The Musical) as young Jim Hopper Jr., Broadway newcomer Nicky Eldridge as young Bob Newby, Emmy nominee Gabrielle Nevaeh (Nickelodeon’s That Girl Lay Lay) as Bob's sister Patty, Rosie Benton (Patriots) as Henry's mother Virginia, and Andrew Hovelson (Lucky Guy) as Hawkins High Principal Newby.

The production will give U.S. audiences a look at the prequel to Stranger Things that also ties into the events of the highly anticipated fifth and final season of the show. The play follows Henry Creel's arrival in town with his family in 1959 Hawkins. It's based on an original story by Stranger Things creators Matt and Ross Duffer, Jack Thorne, and Kate Trefry. Stephen Daldry and Justin Martin serve as director and co-director, respectively.

Alex Breaux's mystery character in 'Stranger Things' season 5. Netflix

Inside The First Shadow, the Stranger Things play expanding the mythology of the Upside Down

"The First Shadow definitely gives fans some not-so-subtle teases and hints as to where certain storylines are heading in season 5," the Duffers previously told Entertainment Weekly in an exclusive interview tied to the London stage production. "It touches on several themes and ideas that we will continue to explore in the show."

Further casting will be announced in January. Performances will begin at the Marquis Theatre on Friday, March 28 ahead of an official opening on Tuesday, April 22.