Jack Black has “hired a personal trainer” and is hitting the gym like a champ now that 2025 is underway as he embarks on the biggest health blitz of his life to date, sources exclusively tell Life & Style.

“Jack has made it his resolution to get really healthy,” an insider says. “He’s not aiming to be super thin or get a six-pack, but he does want to lose enough weight to make sure he’s back in a healthy range for the sake of his longevity.”

Tipsters tell Life & Style that Jack’s boys “are his motivation” because “he wants to be able to keep up with them and be around for them for a long, long time.”

The Jumanji: The Next Level actor, 55, is a proud dad to two sons, 18-year-old Samuel and 16-year-old Thomas, shared with his wife, Tanya Haden.

“He does have a history of yo-yoing with his weight so his plan this time is to make long-lasting lifestyle changes,” say the insiders. “He doesn’t want to drop a bunch of weight and then pile it back on so he’s doing this all very slow and steady.

Life & Style has learned that Jack is not only doing the physical work but also adjusting his diet and daily regimen.

“He’s not completely banning his favorite foods because he wants to be able to stick to this long-term, but he is cutting way back on the sugar and junk food and eating a lot more fruits and veggies,” the sources added.

Just last month, Jack took to Instagram with a video of himself lifting weights to kick off the new year. “It’s about sweat equity. It’s about putting in the work,” the Tenacious D hitmaker said while doing his reps on January 1. “It’s about putting in a grind. It’s about keeping up with the Dwayne ‘Rock’ Johnsons of the world. You see how many I’m doing?! That’s for definition!”

Fans were showing their support in the comments and rooting him on. “The world ain’t ready for Jacked Black,” one fan wrote in response. “You inspired me to work out,” a second commented while a third wrote, “Go get ‘em, Jack! My favorite thing about this video is your outfit.”

Jack has been busy working on new projects including A Minecraft Movie and a new Anaconda film, which is said to be a reimagining of the 1997 horror flick. When he’s not acting or performing, the star enjoys family time. He and Tanya, 53, have been married since March 2006 after dating for less than a year.

“My wife is an incredible singer and also cellist,” he proudly gushed about his longtime love’s talents to People in 2023. “I’d love to collaborate with my wife. She’s a creative force … we haven’t really done anything for a long time. And it would be fun to do something with her.”

As for how they initially connected, “I didn’t date Tanya or talk to her or anything in high school,” he revealed to Parade in 2015. “I was pretty shy. I just watched her from afar. We only started dating like 20 years after high school.”

The Shallow Hal star said that Tanya actually “made the first move” when they reunited at a surprise birthday party for a mutual friend.

“She came up to me and said, ‘Hey, do you ever wanna go get dinner? I should give you my number,’” he said on the “Armchair Expert” podcast in August 2024. “And I was like, oh my God. Heaven opened up above my head, because it was like, this is the thing that I would always want to happen.”