Harry Styles and Zoe Kravitz Pack on PDA With Butt Squeezes in Rome

Harry Styles and Zoë Kravitz have once again taken their love abroad ... the new couple stepped out in Rome and packed on a serious amount of PDA while taking in the sights.

Check it ... the actress and the singer played tourists on Friday, when they held hands while enjoying a stroll in the Eternal City ... though, the duo seemed more interested in each other than the ancient landmarks.

Specifically, HS and ZK couldn't keep their hands off each other during their outing, with Harry -- dressed casually in blue jeans and a t-shirt -- scooping up not gelato, but a handful of Zoë's bum.

You can see the One Direction alum's hand placed comfortably on Zoë's behind, which was just barely covered by an itty-bitty, black slip dress.

Zoë reciprocated the gesture, however ... giving Harry's own bottom a squeeze during their romantic day date.

This outing comes over 2 weeks after the pair first sparked romance rumors thanks to a DIFFERENT stroll in Italy. Since then, the A-listers have popped up together in NYC a number of times, including for a meeting with Zoë's dad, Lenny Kravitz.

Remember, sources previously told TMZ that Zoë and Harry were not exclusive and were just a "friends with benefits" situation ... though, it seems things are definitely progressing quickly.