Jennifer Garner Locking Lips With Boyfriend John Miller in Passionate Pic

Jennifer Garner's got one guy on the brain -- longtime BF John Miller -- and the two were caught locking lips like horny teens outside his L.A. pad.

Check it out ... Jen was all googly-eyed for John -- snuggled up, smooching hard, and straight-up staring into his soul like a woman in love.

There was no glam, no red carpet -- just Jen and John in their everyday getup, sharing a sweet, low-key moment that showed them completely wrapped up in each others' arms, and in their own world.

Looks like this couple is solid ... they’ve been going strong since 2018 after Jen’s split from Ben Affleck, and judging by the honeymoon-level PDA, they’re still all in.

Their PDA also shuts down any recent buzz about Jen reuniting with Ben -- they’re clearly just friendly exes co-parenting their three kids, nothing more.