Chris Pratt strips down to his underwear for an epic fight scene in his new Amazon Prime Video action thriller series “The Terminal List.”

The scene finds the actor being attacked by would-be assassins while he’s undergoing an MRI.

“I used to fight my brother a lot in my underwear,” Pratt joked at the series premiere in Los Angeles. “Oftentimes, we’d run around in our underwear fighting each other.”

Obviously, “The Terminal List” fisticuffs were something quite different. “It was originally choreographed to be a little bit more like a big action fight sequence,” Pratt said. “And I just remember saying, ‘This is a man fighting for his life. I want it to be dirty. So I’m gonna punch him in the balls. I’m gonna rip out their eyes. I’m gonna do everything you wouldn’t do in a sanctioned boxing match, right? It’s not a clean fight. It’s raw, visceral and vulnerable.”

Then he added with a smile, “And you get to see me in my underwear, which is kinda cool.”

Although that proved to be a bit tricky. “We did have to use some visual effects to cover up a few more pieces at various points in the fight scene,” showrunner David DiGilio said, laughing.

“The Terminal List,” based on Jack Carr’s novel of the same name, stars Pratt as a Navy SEAL commander whose platoon is ambushed while on a covert mission in West Asia. When he returns home, he goes on the run when he discovers that secret operatives want him dead.

Pratt explained why he decided to turn the book into a series rather than a movie. “They’ve made this movie before,” he said. “It’s a genre movie and it has to go fast so it’s usually pretty bad. They’re not great movies. They’re kind of like B-movies. We’re really hoping we’ve written a love letter to the thriller genre.”

“The Terminal List” premieres July 1 on Prime Video. The cast also includes Riley Keough, Taylor Kitsch, Constance Wu, Jeanne Tripplehorn, Patrick Schwarzenegger and JD Pardo.