Two of the world's most high-profile technology billionaires - Elon Musk and Mark Zuckerberg - have agreed to fight each other in a cage match. Mr Musk posted a message on his social media platform Twitter that he was "up for a cage fight" with Mr Zuckerberg. Mr Zuckerberg, the boss of Facebook and Instagram parent company Meta, then posted a screenshot of Mr Musk's tweet with the caption "send me location". Mr Musk then replied to Mr Zuckerberg's response with: "Vegas Octagon." The Octagon is the competition mat and fenced-in area used for Ultimate Fighting Championship (UFC) bouts. The UFC is based in Las Vegas, Nevada. Mr Musk, who turns 52 later this month, also tweeted: "I have this great move that I call 'The Walrus', where I just lie on top of my opponent & do nothing." He later tweeted short videos of walruses, perhaps suggesting his challenge to Mr Zuckerberg may not entirely be serious. Meanwhile, 39-year-old Mr Zuckerberg has already been training in mixed martial arts (MMA) and has recently won jiu-jitsu tournaments.