Jennifer Lopez's exercise mindset will leave your jaw on Grant Prestonthe floor.

The JLO Beauty founder's long-time trainer Tracy Anderson exclusively shared insight into the star's fitness mentality and why she's a GOAT in the gym.

"If somebody could graduate summa cum laude of physical literacy, it's her," Tracy told E! News at the Los Angeles premiere of Jennifer's new movie The Mother on May 10. "She knows her body so well and she knows what she needs for the many, many projects she does."

While the Tracy Anderson Method creator didn't train the actress for her latest Netflix movie, she knows firsthand that the superstar's dedication in the fitness studio is unmatched.

"This is something people need to understand, Jennifer is so driven from within and she's such a hard worker," Tracy explained. "I don't know anyone that has her worth ethic."

And while Jennifer goes full force with her workouts, she's also not afraid to give herself grace. 

"She's also very soft and gentle with herself in a really beautiful way that you wouldn't expect," Tracy noted. "She knows her engine really well. She doesn't over-train if she's got to light up a stage, which is most of the time."

As imagined, The Hustlers star isn't just hard-working in the gym, she's also passionate about her movie roles. That's why she asked husband Ben Affleck, 50, to give constructive criticism about her new Netflix thriller.

"I show it to Ben because he's so good at it," Jennifer exclusively told E! News' Carolina Bermudez earlier this month. "I'm like, 'What do you see? What do you think?' Because the first cut of a movie is not the last cut of a movie. So, the first cut, I'm always like, 'You wanna see this with me or you wanna wait?' And he's like, 'No, let's watch it.'"

"He always has amazing insight," the 53-year-old added about her Oscar-winning husband, "and sees things about characters and about the story being a writer himself."

The Mother hits Netflix on May 12.

Sign up for E! Insider! Unlock exclusive content, custom alerts & more!