On Sunday morning, Elon Musk wrote on "X" -- formerly known as Twitter -- that he will be fighting his arch-nemesis Meta CEO, Mark Zuckerberg, in a mixed martial arts cage match. 

"Zuck v Musk fight will be live-streamed on ????," Musk tweeted. He said, "All proceeds will go to charity for veterans."

Earlier this morning, Musk said he was "lifting weights throughout the day, preparing for the fight." He added his days are busy, so he trains at work. 

One Twitter user asked the billionaire: "Elon, what is the point of the fight? Is it to motivate you to work out?" 

He responded, "It's a civilized form of war. Men love war."

On Friday, Musk was curling a 45-pound dumbbell in a live-stream video on X to test the platform's new feature. He said: "This is me curling a 45 so there you go."

Musk first proposed a "cage match" fight with Zuckerberg, who is trained in jiujitsu, on June 20. 

Zuckerberg responded shortly after with, "Send me the location." 

Musk then responded: "Vegas Octagon." 

There has yet to be a time and place confirmed for the cage fight between the two social media billionaires.