David Harbour talks about the ‘grueling’ physical demands for his role in 'Stranger Things season 4'

American actor David Harbour is opening up about how he had to shed 80lbs. for Season 4 of Stranger Things in only eight months in order to properly portray his beloved character as Sheriff Jim Hopper.

"I lost about 80 lbs. from season three — I was about 270 [then], and when we shot [season four] I was around 190," Harbour told British GQ.

The actor explained that in order to properly portray Hopper — who begins the new season held captive by Russians at a labor camp — he lost the weight in just eight months by doing intermittent fasting and Pilates.

"I don't think I'll ever do that again," he told the outlet. "I have this Santa Claus movie [Violent Night] coming out for Universal in December and I gained [it all back]. But now, yeah, never again. The prosthetics are too good."

Harbour's Stranger Things character has been a fan favorite since the hit Netflix series premiered, and interest in the star's physique piqued late 2017 when Merriam-Webster tweeted a clip of him dancing on the show as a visual definition of the term "dad bod."