Stranger Things star David Harbour lost 36kg for new season but 'won't do it again'

David Harbour revealed he lost 36kg for the role but "won't do it again". Photo / Getty Images

David Harbour is opening up about his surprising look in the recent season of Stranger Things.

The actor lost 36kg for the most recent season of the popular Netflix show after his beloved character was imprisoned in a Soviet camp, and now the star has revealed how he underwent his transformation.

Speaking to GQ, Harbour, who plays Chief Jim Hopper, said he enrolled in Pilates and adopted intermittent fasting for eight months while preparing for his character's troubling story line.

"I lost about 80 pounds from season three — I was about 270 [122kg], and when we shot [season four] I was around 190 [86kg]," Harbour told the publication.

"I don't think I'll ever do that again.

"I have this Santa Claus movie coming out for Universal in December" — Violent Night, which purports to be exactly what it sounds — "and I gained [it all back]. But now, yeah, never again. The prosthetics are too good."

Chief Jim Hopper in the first season of Stranger Things. Photo / Netflix

David Harbour lost 36kg for the latest season of the show. Photo / Netflix

Harbour isn't the only Stranger Things actor who went through an intense transformation for the show.

Earlier this week, Jamie Campbell Bower who plays the season four villain, Vecna - also known as Henry or One, admitted he went to extreme lengths to embody his evil character.

The actor regularly spent eight hours in a makeup chair transforming into the relentless character but revealed there was an emotional aspect to the character he had to adopt as well.

The star would sit in a makeup chair for eight hours to transform into Vecna. Photo / Netflix

Speaking to People Magazine the star said, "I would take photographs of each victim," Bower said.

"I'd print them off, my next victim, and I would cross their eyes out and put them up on my wall. And I'd stare at them."

Millie Bobby Brown, who plays one of the show's main character's, Eleven, also underwent a transformation.

When she was cast in the first season as the telekinetic character, the actress - who was only 11 at the time - shaved her head.

She later said it "was the most empowering moment of my whole life".

Millie Bobby Brown shaved her head for the first season of Stranger Things. Photo / Netflix