Terry Crews is taking a candid look back on childhood and his difficult relationship with his father. 

The “Brooklyn Nine-Nine” star dug deep into his past while traversing the Icelandic Highlands on National Geographic‘s “Running Wild With Bear Grylls”. 

“After my time in the NFL, one thing I noticed is that if you make everything sports-specific, all of sudden, when the sport is over, guys just waste away,” said the 52-year-old actor in a preview for the show.

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Telling Grylls about why he decided to prioritize his fitness, the “America’s Got Talent” host explained, “You’ve got to understand, there was a time in my life where I got overweight because I was depressed. I’m depressed, I need something, I need a change, I need to go to the gym 21 days straight. That 21-day period turned into 21 years.”

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“I was naturally just wanting more,” he went on “You’ve got to know, growing up [for me] was not a good experience. My father was very abusive. He used to beat my mother. So it was one of those things where I knew I had to get stronger because one day I thought I’d have to fight him. That’s how it started out.”

Crews also recalled how he felt the need to protect himself and his family from the time he was just five years old.

“I always, always had been like, ‘Be fit, be ready, be prepared, be there,'” he added. “But even then it’s hard, because certain things did trip me up that I had to get over.”

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“Running Wild With Bear Grylls” airs Monday on National Geographic at 9 p.m. ET.