Kamala Harris took a break from serious campaigning to have some lighthearted fun ... receiving raucous applause during the last "Saturday Night Live" before the election.

The VP stopped by Studio 8H at 30 Rockefeller Plaza for Saturday night's cold open ... appearing in the mirror across from Maya Rudolph -- who has portrayed the veep on and off since 2020.

Ya gotta watch the clip for yourself ... after a pretty generic opening with Dana Carvey, Andy Samberg and other 'SNL' stars playing their usual characters, MR says she just wants to chat with someone who understands what she's going through -- a Black and Southeast Asian woman and former prosecutor running for President of the U.S.A.

Of course, that list is just her ... so, the real Kamala appears in the mirror, saying "You and me both, sister" -- a line completely drowned out by the huge cheers from the audience.

Kamala fires a shot off at Donald Trump saying Maya's Kamala can totally win the election 'cause she can do things her opponent can't ... namely, open doors. It's a reference to DJT's trouble opening the door to the garbage truck he drove around in earlier this week.

The silly skit then diverges onto a back-and-forth between the Kamalas ... who rhyme their name with a whole lot of common words and phrases -- like "pajamalas" instead of pajamas and "Keep Calmala and Carry Onala" instead of "Keep Calm and Carry On."

The skit ends with the two arm-in-arm ... launching the show with the iconic phrase "Live from New York, It's Saturday night" -- before host John Mulaney took the stage next to deliver his monologue.

Kamala had a busy day ... speaking at a rally in Atlanta this morning -- and, while she's headed for Detroit for some last-minute campaign events, Air Force 2 rerouted to NYC for this appearance, a surprise to the press pool onboard according to some reports.