The pair were spotted kissing and getty cozy while vacationing on Italy's Amalfi Coast earlier this week.
The Wet Hot American Summer actor, 40, and the Russian model, 29, locked lips on the stone beach. Cooper, wearing orange swim trunks, seemed to only have eyes for Shayk, who donned a blue bikini top chicly mismatched with her neon-orange-and-black bottoms.
"They were very playful and loving," an observer tells PEOPLE. "They were completely wrapped up in one another and having a great time."
The actor fiddled with Shayk's barely-there suit as they soaked up the sun. He kept a pair of goggles on his head, seemingly at the ready for their next plunge.
A source tells PEOPLE that the couple stayed at Le Sireneuse, a luxury hotel in Positano. Over the years, the hotel has attracted a slew of famous clientele, including Gwyneth Paltrow and boyfriend Brad Falchuk.
Ydo Sol / Courtesy Le Sirenuse
The model also attended a performance of Cooper's The Elephant Man in London later that month.
Cooper split from girlfriend Suki Waterhouse, 23, just a few months before linking up with Shayk.