David Harbour has undergone an unbelievable transformation for the latest season of Stranger Things - but it's not been easy.
The star shed a whopping 70lbs as his character, Jim Hopper, was taken prisoner.He opened up about the grueling process when speaking on Tuesday's BBC Breakfast and admitted: "It's not easy, it's a lot of not eating when you lose that much weight, and being hungry."
He then joked: "That's the secret, if you're curious about the diet secret, it's just not eating food."
WATCH: Stranger Things - see the volume four part two teaser
David had to work incredibly hard to shed the pounds and confessed to GQ: "I was about 270 [in season three], and when we shot season four I was around 190."
His weight loss method included intermittent fasting and a lot of Pilates, but he doesn't want to do it again. "I don’t think I'll ever do that again."
David only made the transformation for the small screen as he's now back to his original weight. "I gained it all back," he added. "But now, yeah, never again. The prosthetics are too good."
David Harbour lost a series amount of weight for season four
The star's interview comes amidst a turbulent time for Stranger Things as the show's creator Matt Duffer had to defend it after receiving criticism from its star Millie Bobby Brown.
The actress, who plays Eleven in the hit Netflix series, criticized the writers for failing to kill off some of the show's main characters.
In an interview with TheWrap back in May, she said: "It's way too big. Last night, we couldn't even take one group picture because there was like 50 of us. I was like, 'You need to start killing people off.'
David shed 70lbs for the new season
"The Duffer brothers are two sensitive Sallies that don't want to kill anyone off. We need to be Game of Thrones. We need to have the mindset of Game of Thrones.
"They tried killing David [Harbour] off and they brought him back. It's ridiculous," she added.
When the brothers were asked about Millie's comments in the latest edition of the Happy Sad Confused podcast, Matt responded: "I've heard. What did Millie call us? She said we were 'sensitive Sallies'. She's hilarious."
He then defended the writers' decision to keep the show's main characters alive, with a lengthy explanation which can be read here.
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