Paul Pierce says the Celtics-Lakers rivalry is officially back on ... with Kyrie Irving playing the Bird/Pierce role -- and LeBron James playing the Magic/Kobe role!!
We got Paul out at LAX this week and, as one of the key players in the historic NBA clash -- he declared to TMZ Sports the two teams can finally have a real tiff again now that Bron's in L.A.
"It's on. It's on," the Celtics legend tells us. "The rivalry is back. For sure. It's official."
Pierce tells us LeBron and Kyrie will fill the leader-of-the-team roles well ... and he seems stoked to see it this season.
By the way ... if you were wondering if Pierce has any inkling to come back to the NBA and be a part of that rivalry one last time -- he says no chance.
"I'm off!" he tells us.