The wild cage match might actually happen ... 'cause the Meta CEO just clapped back at the Twitter honcho's callout by saying he's totally down to fight!!

Musk recently pitched the fight idea in response to a report claiming Zuck's company is planning to rival Twitter with a new platform of its own ... to which he replied, "I'm up for a cage match if he is lol."

Whether or not he was kidding, the Facebook co-founder got wind of Musk's tweet ... and channeled his inner Khabib Nurmagomedov by saying, "Send me location."

The response, according to The Verge, was NOT a joke ... and he's 100% serious about duking it out.

Musk, 51, already seems to have a spot in mind for the potential fight ... tweeting "Vegas Octagon" late Wednesday night.

He also teased some of his skills ... adding, "I have this great move that I call 'The Walrus,' where I just lie on top of my opponent & do nothing."

Musk better pray the move works, 'cause Zuck, 39, started honing his craft back during the pandemic ... and he recently competed in a jiu-jitsu tournament, where he earned a gold and silver medal.

He also claims to have finished the famous "Murph Challenge" -- a one-mile run, 100 pull-ups, 200 push-ups, 300 squats, and an additional one-mile run (all while wearing a weighted vest) -- in under 40 minutes, which is quite an accomplishment.

Controversial former kickboxer/media personality Andrew Tate is down to have Elon's back, though ... 'cause he said he wants revenge for being blocked on all Meta platforms.

Somebody get Dana White on the phone ASAP.