WASHINGTON — Retiring President Biden appeared in public Thursday for the first time since turning 82 — jokingly asking the NBA championship-winning Boston Celtics to confirm “you’re Celtics, right” in brief public remarks before dribbling a basketball in front of a crowd.

Biden, who notched another presidential age record with his birthday Wednesday, spoke for about 5 minutes on the South Lawn as he hosted members of the team — and scandal-plagued first son Hunter Biden, 54, was spotted in the crowd.

“Welcome to the White House. I didn’t know any of these guys behind me, but they just showed up. I don’t know where the hell they came from,” Biden opened, referring to members of the team arrayed behind his lectern.

“2024 NBA champions the Balls — you’re Celtics, right?” he went on, turning around. “The Boston Celtics.”

It’s unclear if Biden was attempting to make a joke about the perception of his fading mental acuity, over which fellow Democrats forced him to relinquish the Democratic presidential nomination in July in favor of Vice President Kamala Harris, who went on to lose the Nov. 5 election.

Biden told the 18-title-winning team that his Secret Service name is also “Celtic” — calling himself an “an old Irish Celtic,” referring to his ancestry in the British isles.

The Biden family’s other code names also begin with “C” — with Hunter, who is awaiting sentencing for gun and tax crimes, known as “Chieftain.”

It’s unclear if the outgoing president will pardon his son before leaving office on Jan. 20.

Biden, who just returned Tuesday night from a nearly weeklong South America tour where he repeatedly snubbed the press, again took no questions from journalists Thursday.

Biden’s silence has roiled the press — as he continues to remain mum on his decision to allow Ukraine to use US rockets far inside of Russia and about President-elect Donald Trump’s transition, which he claimed earlier this year posed the risk of ending American democracy.

The lame-duck president, however, worked the rope line and posed for a number of selfies after being presented with a gifted Celtics jersey bearing his name.

One spectator tossed him a basketball, which he dribbled on the White House’s driveway while smiling before returning inside.