Sydney Sweeney filming her new rom-com ‘Anyone But You’ at the Australian coast.

Sydney Sweeney in Australia filming her new rom-com movie 

Sydney Sweeney & Glen Powell in Australia filming the new rom-com movie

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

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?