John C. McGinley has joined the cast of “Guardians of the Galaxy” director James Gunn’s new horror film, “The Belko Experiment.”

Gunn made the announcement Thursday on his Facebook page. He also revealed castings this week of “Fruitvale Station’s” Melonie Diaz, “The Newsroom” star John Gallagher Jr. and “Scandal” president Tony Goldwyn.

“When I think of John, I often think of Bob Slydell from ‘Office Space,'” Gunn said. “Fortunately, in that film, the characters only had to murder each other spiritually, and not physically, as they do in ‘Belko.’ John may be most recognized from ‘Scrubs,’ but he’s an eerily dexterous actor who can do almost anything and has shone in any role he’s been given. He most recently got rave reviews for his performance in ‘Glengarry Glen Ross’ on Broadway with Al Pacino and Bobby Cannavale.”

McGinley will play a socially awkward top exec at Belko, and longtime friend of Tony Goldwyn’s character.

The story, directed by Greg McLean from Gunn’s script, follows an American company after it’s mysteriously sealed off in South America. Employees show their true colors when they are ordered to kill each other or risk being killed themselves.

Gunn, who is producing with Peter Safran, is also on board to direct and produce Marvel-Disney’s “Guardians of the Galaxy 2,” which will hit theaters on May 5, 2017.