Christmas is coming early for Kobe Bryant -- the Lakers are planning to retire his jersey before the Warriors game on Dec. 18 ... multiple sources tell TMZ Sports.  

The Lakers aren't officially acknowledging it -- but the team sent a letter to Lakers season ticket holders advising them to "hold on to your tickets for the game on Dec. 18" for a "special event."

We've made some calls and everyone's saying the same thing ... it's Kobe's big night. 

The big question ... which number will go up in Staples Center -- #8 or #24 ... or both? (Our money's on both). 

The Lakers also play the Golden State Warriors that night -- so LaVar Ball can finally watch Lonzo take on Steph Curry

Those tickets are gonna be PRICEY on StubHub.