Chris Hemsworth has become known as an action hero thanks to his role as Thor in the Marvel Cinematic Universe, but his real-life death-defying stunts Disney+ reality series Limitless had Marvel Studios worried the actor could be seriously injured and pulled the plug on the shore until he completed filming on Thor: Love and Thunder.

Limitless has seen Chris Hemsworth throwing himself into action-packed stunts, including climbing to the top of a cable car using only a rope while suspended 100 feet in the air, swimming in Arctic waters, and several other experiments designed to test the boundaries of the human body. The series was created by Darren Aronofsky, director of The Whale, and also features an appearance by Hemsworth’s brother Liam.

Hemsworth revealed in a new interview with Jimmy Kimmel Live that Marvel Studios began to get worried about him potentially doing himself serious harm after he injured his ankle while training for one of the many challenges he faces in the series. While Hemsworth believed that he could squeeze in filming for the show before his latest Thor appearance, it ended up having to wait due to Marvel getting nervous about their star. However, as he explained, returning to do the stunts after filming as the God of Thunder brought its own challenges. He said:

“I said, ‘Great, we’ll do it before I shoot ‘Thor,' Anyway, I started training, I blow my ankle out, and Marvel stepped in and said, ‘No. The show that might kill him, you can do that after our film.’ It’s about time I came to actually shoot, I was at the end of ‘Thor,’ and I was Thor size, and my trainer looked at me and said, ‘You’re screwed. This is going to be the hardest thing you’ve ever done.' [The challenge] would not even be about strength, it became the will to fist fight to try and get up the thing.”

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Chris Hemsworth May Be Done With Insane Thor Training

Chris Hemsworth in Thor: Love and Thunder
Marvel Studios / Disney

Even though we know that Thor will return, Chris Hemsworth has said that he may think twice before bulking up quite as much for his next time out. Having gone through an insane amount of training to deliver his “God Bod” in the movie, he previously suggested that he won’t be going to quite the same extremes the next time he plays the character. He said:

“Each time I’ve played the character and put the muscle on and put the size on, and then lost it for something else and played another character, there’s muscle memory, and I used to say it sort of got easier each time. This was particularly hard. I think because the target weight we aimed for was quite a ways above where I’d been before. We had 12 months when I was at home, just training and sort of, you know, puppeteering the body and manipulating and trying to like, ’Okay, we could try more swimming now or try more martial arts. It was a really fun exploration, but I don’t know that I wanna get that big again. But I was sort of… It was… Yeah, it was just exhausting. I don’t know, maybe I’m getting old, but things just started to hurt more.”

Limitless premieres today on Disney+, where you can also find all of Hemsworth’s Thor outings.