Johnny Manziel is bringing the party train to Vegas this weekend -- at least, that's the plan ... 'cause his name has popped up on the celebrity guest list for UFC 196, TMZ Sports has learned.
Sources connected to the situation tell us Manziel is just one of the HUGE stars who's arranged to attend the McGregor vs. Diaz megafight -- and we're told UFC has a prime seat ready for the QB.
If he shows up, he'll be surrounded by some of the biggest stars on the planet ... including Leo DiCaprio, Bruno Mars, Gerard Butler, Gordon Ramsay, Niall & Liam from One Direction and Josh Brolin.
That's not all ... we're told Reggie Bush, Tyga, T-Boz, Marcedes Lewis, Zac Brown and Danny Elfman are also on the list.
As for Manziel, it's an interesting PR move -- on one hand, it's Vegas (not great for his party boy image). On the other hand, it's a huge sports event ... so, what's wrong with being a fan?