'Euphoria' Star Sydney Sweeney & Glen Powell Show Off Beach Bodies Filming New Project

Sydney Sweeney and Glen Powell are havin' some fun in the sun ... all smiles while down under filming their latest project.

The duo's spending some time near Sydney, Australia for their latest film -- a romantic comedy with "Easy A" and "Friends with Benefits" director Will Gluck leading the shoot.

Not much has been said about the mystery project, but Sydney and Glen have been reported as the stars ... and we now know it's gonna feature their rockin' bods frolicking in the ocean.

They both were splashing around with Alexandra Shipp and Hadley Robinson -- 2 actresses who are costarring in the film. We're told the cameras weren't rolling when they were spotted, so this is just coworkers having some after-hours fun.

Looks just like your happy hours, right?

FYI, the "Euphoria" star's also taking on the role of executive producer for this one ... that's a first for her career.