Stipe Miocic on Cormier's Secret Training with Steven Seagal, 'He's a Savage!'

Yep, Stipe Miocic has seen that footage of Daniel Cormier training with Steven Seagal back in the day ... but he ain't worried about it!

The footage was shot back in 2015 when Cormier was getting ready to fight Jon Jones at UFC 182.

Seagal -- who considers himself a martial arts expert -- hit it off with Cormier and offered to share some of his secret fight moves ... but only if UFC turned off the cameras.

Cormier and UFC obliged, and now -- in theory -- he's been trained up in the ways of the guy from "Under Siege."

So, when we spoke with Stipe this week as he preps to headline UFC 252 on Saturday -- we had to ask if he was concerned that Cormier could unleash some of that "Hard to Kill" knowledge on him during their final fight?

Spoiler Alert: Stipe ain't worried ... but he was complimentary of the actor.

"Seagal's a savage. Ya gotta look out for that guy."

There's more ... Stipe also told us why he's not planning to retire any time soon and why he doesn't feel bad sending Cormier into retirement with an "L."