Dallas Cowboys wide receiver Dez Bryant was officially welcomed to the Roc Nation Sports family this weekend with a huge party at Jay Z's NYC nightclub ... complete with champagne, hot chicks and expensive jewelry.
It all went down at Jay's 40/40 Club ... where Dez sipped on expensive Ace of Spades champagne and D'USSE Cognac.
Also, check out Dez's brand new chain -- the Roc Nation Sports logo -- we're guessing a gift from his new agency.
Of course, Dez fired his old agent and signed with Jay's group earlier this month -- and clearly, he's fired up about it.
Dez becomes a free agent after this season -- which means it's time to see if Jay can get him a 9-figure contract to match that necklace.