This comes just after Musk tested a live video feature on X.
The social media moguls have been egging each other into a mixed martial arts cage match in Las Vegas since June.
"Zuck v Musk fight will be live-streamed on X. All proceeds will go to charity for veterans," Musk said in post on X early on Sunday, without giving any further details.
Musk added that the “proceeds will go to charity for veterans.”
Meta did not immediately respond to a Reuters request for comment on Musk's post.
Also read: Musk tests live video on X