The 2x WWE Hall of Famer, who's been out of the squared circle for years, tells TMZ Sports he will wrestle Friday night under the independent promotion, Game Changer Wrestling.

"I'm returning to the ring for the first time in about 3 years," X-Pac told Babcock and Mojo on the "TMZ Sports" TV show (airs weeknights on FS1).

Then the wrestling legend dropped this bomb ... "I had ACL surgery last year. I had a torn ACL for about 14 years."

X-Pac, government name Sean Waltman, has been living life with a torn anterior cruciate ligament (ACL).

Now that the injury was repaired, Waltman says he expects to put on a helluva show in the ring.

"This is my first match back where I can actually do some good, really good stuff in there."

And, X-Pac believes he's still got it ... but when he no longer does, that's when he'll walk away for good.

"I expect it to go well," he says, adding ... "and if it does, I'm going to have matches until I can't have good matches anymore."

X-Pac's been in the biz for over 30 years ... wrestling for everyone from WWF, WCW, WWE, and TNA, just to name a few.

He was inducted into WWE's Hall of Fame twice -- once in 2013 and again in 2020 -- the second time around as a member of the wildly popular "NWO" faction.

The NWO AKA "New World Order" was a group that featured some of the industry's biggest stars -- Hulk Hogan and Scott Hall, also known as Razor Ramon.