Tim McGraw Says Faith Hill Told Him to 'Get Over Yourself' Before He Lost 40 Pounds (Exclusive)

ET exclusively spoke with the 52-year-old country star at his Nashville gym.

Tim McGraw is in the best shape of his life -- and he owes it all to his family. 

ET's Nischelle Turner exclusively spoke with the 52-year-old country star at his Nashville gym, TRUMAV, on Saturday, where he opened up about his incredible transformation and revealed that it all started with his wife, Faith Hill, telling him to "get over yourself." 

"That's a big one," McGraw confessed, before noting that Hill wasn't the only one ready to whip his butt into shape. His next "ah-ha moment" came when his daughter, Gracie, who was "11 or 12 at the time," saw him on a giant movie theater screen as the trailer for his 2008 movie, Four Christmases, played. 

"My daughter looked over at me and said, 'Jeez, Dad, you need to do something,'" he recalled. "It got me thinking, you know, I want to be around. I want to be around to see my grandkids. And I want to be around to see what these kids do with their lives, you know?" 

"There's a certain amount of writing it off a little bit because it's part of the syntax of a relationship," he said of Hill's warning before Gracie's big observation. "And when your kids [say it], kids are so honest."

McGraw was surrounded by professional athletes growing up. His father, Frank "Tug" McGraw, was a star pitcher for the New York Mets and the Philadelphia Phillies. "It's in my DNA. I was an athlete my whole life growing up and I just let it get away from me," he confessed. 

The "Humble and Kind" singer attributes some of his weight gain to the "musician's lifestyle." He later joked during ET's interview that "all the other country artists are building bars and I'm building a gym." "Everything was good. My career was good," he remembered. "I was just pretty lazy in my life." 

McGraw ended up losing 40 pounds, but for him, it wasn't about the weight -- it was about getting healthy. "I didn't start with gym memberships. I didn't start with trainers. I didn't start with any of those things. I started by walking every day," he revealed. "The more I walked, the more I wanted to do and the more I wanted to do bodyweight stuff. So, that gym stuff wasn’t part of my program for a while."

The singer advised that fans at home "take that first step." "Just say, 'I'm gonna walk 10 minutes at 7 a.m. or 8 a.m. or 9 a.m.,' whatever your wakeup time is. 'I'm gonna walk 10 minutes today.' You do that for 10 weeks and I guarantee it'll lead to something else," he shared. 

Fans can learn more about McGraw's fitness journey with his new book, Grit & Grace: Train the Mind, Train the Body, Own Your Life, available now. The lifestyle book dives into some "dark places" in McGraw's life, and how he was able to get out of them. 

"You're gonna fail, but what I've realized is putting myself in a better position physically and mentally gives me the opportunity to get back up quicker," he said. "Life's not about the failures that you have, it's about how you react and the way you react to those failures is what propels you forward."

McGraw opened his gym, TRUMAV, earlier this year. "I wanted to start something that sort of reflected what I did every day and what we did on the road. I just wanted to do something good that maybe helps people," he explained of his new endeavor. 

As for McGraw and Hill's 22-year-old daughter, Gracie, she and her sisters are still inspiring their dad. Gracie's recent car duet with McGraw recently appeared on his Instagram. 

"She made me cry, watching that. She's such a spark, that girl," he gushed. "She's a spark plug and she's out there, she's out waiting tables and doing auditions right now."

"She wants to be an actress and she's a fantastic actress, so that's her goal in life and I'm always trying to get her to make a record 'cause I think she's a great singer," McGraw added. "I'm so proud of them all because they do things, they have a really good drive about them and that's what you want, is a drive."

Grit & Grace: Train the Mind, Train the Body, Own Your Life, is available now.