WASHINGTON — Lame-duck President Biden and Vice President Kamala Harris appeared in public together Monday for the first time since the veep’s loss to President-elect Donald Trump — making a joint visit to Arlington National Cemetery for a Veterans Day event.

Biden, 81, and Harris, 60, participated in a wreath-laying ceremony ahead of the retiring president’s remarks hailing military service members and their families — as the defeated Democratic nominee looked on from the stands with an expressionless first lady Jill Biden on her left.

Harris, who did not speak, wore a similarly stoic expression before swapping smiles with her husband, Douglas Emhoff — seated on her other side — just six days after losing to Trump, 78, whom she denounced last month as a “fascist” who threatened American democracy.

“This is the moment to come together as a nation, to keep faith in each other,” Biden said in what appeared to be a reference to the Republican takeover of the White House and Congress in last Tuesday’s election.

“The world is dependent on each of you and all of us, all of you, to keep honoring the women and the men and the families who have borne the battles, to keep protecting everything they fought for, to keep striving to heal our nation’s wounds, to keep perfecting our union.”

It’s unclear whether Biden, who will host Trump Wednesday at the White House, spoke with Harris during the visit to the cemetery.

Harris’ motorcade briefly stopped at a gravesite in Section 13 and she knelt at a grave, according to a pool report.

That area of the cemetery primarily holds the bodies of men who fought in the Civil War.

The VP’s office did not immediately offer information on that stop.

Biden and Harris addressed her defeat separately last week — with the latter losing both the popular vote and the Electoral College.

Harris delivered a concession speech Nov. 6 at Howard University, her alma mater, and gave a speech that some commentators believed was designed to position her as the potential future leader of the Democratic Party as it begins a period out of power.