Mark Zuckerberg has been training with UFC stars.

The 39-year-old billionaire is best known as the founder of Meta but on Tuesday was pictured with sports stars of the Ultimate Fighting Championship Alex Volkanovksi and Israel Adasanya, who shared a snap of them together at the gym in Lake Tahoe, Nevada.

He captioned the post: "No fugazi with Mark, This is Serious Business!!" and emblazoned the post with an emoji of a shark.

In the comments, Facebook founder Zuckerberg said that it had been "an honour to train" with the UFC stars as he prepares to fight Elon Musk, the owner of rival social networking site Twitter.

Towards the end of June, Tesla founder Musk - who is the richest man in the world with a net worth of $237.7-billion whilst Zuckerberg is thought to be worth $105.7-bn - took to Twitter to tell Zuckerberg: “I’m up for a cage fight.”

Zuckerberg, whose company has just launched a “Twitter killer” micro-blogging site said to be called Threads, replied by sharing Musk’s tweet with the caption: “Send me location.”

A Meta spokesperson commented: “The story speaks for itself,” while Musk replied to Zuckerberg by suggesting a venue by stating: “Vegas Octagon.”

Musk also shared details of his imaginary fighting technique, playfully dubbed “The Walrus”, which he joked involved him lying on top of his opponent and doing nothing.

Musk also tweeted: “I almost never work out, except for picking up my kids throwing them in the air.”

Zuckerberg on the other hand has been training in mixed martial arts and recently won jiu-jitsu tournaments.