Here's Celtics rookie stud Jayson Tatum learning the hard way that he hasn't completely made it yet, getting rejected -- more than once -- at one of the hottest clubs in Tinseltown.
It went down Wednesday night when the 19-year-old -- who's a Rookie of the Year contender -- tried to get his turn up on at Warwick in Hollywood, a 21 and over joint.
Warwick is known for sticking to its guns when it comes to the age requirement ... after all, D'Angelo Russell got denied in 2016 when he was just months from turning 21.
We're told J.T.'s teammate Kyrie Irving got through the door without a hitch ... which makes sense 'cause he's 25.
Oh BTW, Celtics did beat the Clippers earlier that night ... so at least there's that.
Try again in 2020, bro.