Don't mess with Dwayne Johnson's workouts!

The Rock was all smiles in shorts and a green hoodie as he posed with a group of fans from the Livestrong foundation in Savannah, Georgia. He captioned the Instagram with an inspirational message -- and a warning!
 

WATCH: Dwayne Johnson Proves He's a Real-Life Hero, Visits Sick Kids During 'Baywatch' Break 

"Had to stop my workout for 10mins to meet some incredibly strong survivors from the #LiveStrongFoundation," he posted, thanking the group for sharing their stories with him.

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"You can live three weeks without food, three days without water, three minutes without oxygen, but only three seconds without hope," he added. "Stay strong, guys, and keep inspiring all those around you and defying the odds."

But then, things got real serious real quick.

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"Ps - aaaaaand to anyone reading this thinking, 'Oh, you can just go up and disturb Rock's workout and he'll take pics.' Don't do it," he warned. "I'm there to work and you should too. Kindly just pass the silverback on by or I'll rip your face off. Have a nice day."

Noted!!!

It's no surprise that Johnson takes his workouts super seriously. Have you seen the first photos from the set of "Baywatch?!" Even if you have -- they're worth a second look.

WATCH: Dwayne Johnson and Zac Efron Are all Muscle as 'Baywatch' Starts Filming