Musk is an interesting one considering it would be his first major public appearance since agreeing to step down as CEO of Tesla.
Other names expected to be at the October 6 fight ... Rory McIlroy, Matt Damon, Anthony Kiedis, Megan Fox, Under Armour CEO Kevin Plank, Joel Kinnaman and Mark Consuelos.
We also got Mike Tyson out on Monday -- and he told us he'll be at the fight too!
Of course, Mike is tight with UFC honcho Dana White ... and he's become a big MMA fan over the years.
Tickets for the fight are getting super pricey -- the cheapest seats on StubHub are going for $650 a pop ... and the good seats are running up to $27,000!!!!!