Trey Lance will DEFINITELY be poppin' bottles for his 21st birthday this week -- 'cause E-40 just gifted the new 49ers rookie QB with a TON of his signature booze!!!
FYI -- the Bay Area rapper is a HUGE Niners fan, and was stoked when S.F. selected the former North Dakota State star with the 3rd overall pick in last month's draft.
So much so, in honor of Lance joining the squad -- and to celebrate his 21st birthday on Sunday -- E-40 hooked him up ... BAY STYLE!!!
TMZ Sports has learned the 53-year-old delivered NINE bottles of his own booze to the new S.F. rookie -- including 3 bottles of his E. Cuarenta tequila, 3 bottles of his Earl Stevens Selections Wine and 3 bottles of his Tycoon Cognac.
As for why 3 each ... we're told the number just felt right given Lance was the #3 overall pick.
E-40 even wrote a personalized note to Lance to pair with the drinks ... writing to the rookie, "Welcome to the Bay and happy birthday King."
"Know this is a big moment for you, so wanted to send over some bottles from my brands for you and your family to celebrate!"
"Best of luck this season. Go Niners!"
Dope gift ... now drink responsibly, Trey!