Yes, LeBron James is a Disney Warner Bros. princess.
MultiVersus - LeBron James

Warner Bros. Games announced three additional fighters that will be added to the roster of MultiVersus. These include professional basketball player LeBron James, along with both Rick and Morty from Rick and Morty.

How does LeBron James fit into the Warner Bros. universe you may ask? Well, it's because James started in Space Jam: A New Legacy in 2021.

James will utilize "unbeatable basketball moves, from dunks and alley-oops to assists and ball ricochets, and more." He will be playable when the open beta for MultiVersus begins on July 26.

As for Rick and Morty, they'll be coming later. Morty will be available when Season 1 for MultiVersus begins on August 9 while Rick will also be in Season 1 but will be coming later on during said season.

MultiVersus - Rick and Morty

Rick Sanchez, the mega-genius scientist, will bring a number of abilities to MultiVersus, many of which utilize his signature portal gun and can be strategically combined with his other tricks, like summoning Meeseeks. Morty Smith, Rick’s teenage grandson and sidekick on countless adventures, will have a mix of skills with an emphasis on projectiles and counter moves, including grenade weapons and the ability to whip himself at opponents.
The MultiVersus open beta runs from July 26 through to the game's release in August. You can play it on PlayStation 4, PlayStation 5, Xbox One, Xbox Series X|S, and PC. You can get access to the beta through Twitch Drops, buying a Founder's Pack, or if you participated in the previous closed alpha test for the game.

MultiVersus is an all-new free-to-play platform fighter in development by Player First Games that introduces a team-based 2 vs. 2 format combined with an all-star cast of iconic characters, including Batman, Superman, Wonder Woman and Harley Quinn (DC); Shaggy and Velma (Scooby-Doo); Bugs Bunny and Tasmanian Devil a.k.a. Taz (Looney Tunes); Arya Stark (Game of Thrones); Tom & Jerry; Jake the Dog and Finn the Human (Adventure Time); Steven Universe and Garnet (Steven Universe); Iron Giant (The Iron Giant), LeBron James (Space Jam: A New Legacy); Rick Sanchez and Morty Smith (Rick and Morty), an extraordinary original creature named Reindog; and many more to come.