Birdman -- $500,000 BDAY PARTY ... Champagne, Celebs, Hotties & Bugattis

Birdman's on a mission to throw one of the most insane 45th birthday parties known to mankind -- a "Half a Milly" bash -- filled with endless champagne, naked models, the entire Young Money crew ... and his $7 MILLION car collection.

The party's set to go down in New Orleans Saturday night -- in the middle of NBA All-Star Weekend. Birdman rented out a private venue ... which he's renamed "Birdman's New Era Voodoo Lounge."

In addition to 30 body-painted naked models, 700 clothed models will be on hand -- lubricated by 150 cases of GT vodka, $100,000 of Belaire Rosé, and 20 cases of some anti-hangover cocktail.

Birdman's shipping in his $7 million car collection from Miami ... including his red Bugatti, white Bugatti, 2 Maybachs, and 3 tour buses.

The guest list is sick -- party host JJ Jones tells us, James Harden, Paul George, Blake Griffin, Shaq, and Kenny Smith are coming ... as well as Young Money rappers Lil Wayne, Drake, Nicki Minaj, and more.

If that's not cool enough -- the original Cash Money crew's expected to get together for the first time in nearly a decade ... including Mystikal, Turk, Juvenile, and Mannie Fresh.