Mark Zuckerberg is not joking around about training hard. The jiu jitsu-loving Meta CEO showed off his abs Tuesday in an Instagram post with UFC champions Israel Adesanya and Alexander Volkanovski, flexing his muscles ahead of a rumored cage match with rival billionaire Elon Musk. “No fugazi with Mark 🦈,” Adesanya captioned the post. “This is Serious Business‼️” In response, Zuckerberg commented “It’s an honor to train with you guys!” Musk appeared to challenge Zuckerberg to a “cage match” in late June, which the Facebook founder was quick to jump onto by responding, “Send Me Location.” UFC President Dana White confirmed to The New York Times that the two billionaires are serious about their proposal and have spoken to White several times about organizing it. “We have two guys that have never professionally fought, and they’re in two completely different weight classes,” White said.