Kevin Hart and Tons of Celebs Celebrate at his 40th Birthday Party

Kevin Hart celebrated his big 4-0 in grand fashion, and tons of celebs were on hand to ring in Kevin's new decade on earth.

As for who showed up at L.A.'s TAO restaurant ... well, for starters, LeBron James, Don Cheadle, Meek Mill, Chris Paul, Nick Cannon, Usher, Evan Ross, Draya Michele, Karrueche Tran, Marlon Wayans, Michael Ealy, Gabrielle Union ... shall we go on.

The dinner was at TAO, and the party will be continuing through Sunday on to The Highlight Room. TAO and The Highlight Room are connected to Dream Hollywood ... one the hottest hotels in town.

Kevin predicted the party would be amazing, saying, "A pool party like you've never seen before."