While Elon Musk has been busy rebranding Twitter as X, his rival Mark Zuckerberg has been rising up the ranks to receive his blue belt in Brazilian Jiu-Jitsu.

On Sunday, the Meta CEO posted a photo of himself sporting his new colors with martial arts coach Dave Camarillo.

“Congrats @davecamarillo on your 5th degree black belt, Zuckerberg wrote. “You’re a great coach, and I’ve learned so much about fighting and life from training with you. Also honored to be promoted to compete at blue belt for @guerrillajjsanjose team.

A blue belt in Brazilian Jiu-Jitsu is the second adult rank in the art after a white belt.

Zuckerberg seems to be serious about the sport. He picked it up during the pandemic. In May, he won two medals in a Brazilian Jiu-Jitsu tournament at a Silicon Valley high school.

Training for the cage match?

In June, Elon Musk challenged Mark Zuckerberg to a battle of the billionaires, saying he was “up for a cage fight.”

Zuckerberg responded by posting a screenshot of Musk’s tweet on his Insta Story with the caption, “send me location.”

Musk then responded with two words: “Vegas Octagon.” He was later photographed training with Lex Friedman, who has a black belt in Jiu-Jitsu.

Dana White, president of the UFC, told the New York Times that he has talked to Musk and Zuckerberg about organizing a fight.

“They both want to do it,” he said.

Zuckerberg’s latest post seems to signal he’s serious about improving his skill level.