Ben and Jen were together Monday at the Met Gala in New York City, where they were locking arms, hugging and kissing through their face masks.

J Lo wore a brown ensemble complete with a plunging dress and a long train, plus a hat, necklace, and a feather boa. She's also got an interesting accessory around her neck, something like a big choker.

Ben, meanwhile, went with a more classic look in his tuxedo ... kinda like he did last week at the 78th Venice International Film Festival, when they went to their first showbiz event together since reuniting.