Timothee Chalamet Makes Out with & Serenades GF Eiza Gonzalez in Mexico

Timothee Chalamet has a new boo to call him by his name -- one Eiza Gonzalez ... who's quite generous with the PDA, especially when they're chillin' out in her homeland.

Timmy and Eiza -- a Mexican actress he now seems to be dating after breaking up with Lily-Rose Depp -- are down in Cabo San Lucas for a romantic getaway with some in friends in tow. It's clear they're together ... he laid a wet one on her at one point.

But, the romancin' didn't end there -- TC picked up a guitar while they were all hanging poolside and started jamming out for Eiza and co. New GF seemed to dig that gesture too.

Eventually, young Tim lost the shirt and joined Eiza for a dip in the water. They definitely look good together -- especially Eiza, who showed off her hot bod with a two-piece bikini.