Zac Efron went on a sexy, shirtless horseback riding adventure with new hookup Michelle Rodriguez Credit: Ciao Pix/FrezzaLaFata/AKM-GSI

Cowboy, take Us away! Just when you think Zac Efron can't get any hotter, he goes and does something like shirtless horseback riding. The Neighbors actor, 26, looked like a cover model for some steamy romance novel on Monday, July 7, when he and new hookup Michelle Rodriguez went for a ride in Sardinia, Italy, where they've been vacationing with friends.

Efron showed off his uber-ripped physique by stripping down to just a pair of black jeans for the adventure. His sculpted abs and biceps were on full display as he and his majestic steed trotted along the sandy shore of a lake, and then into the shallow surf.

Rodriguez, meanwhile, sported a black crop top, low-rise black leggings, and black riding boots. She took the reins of a white horse, while Efron and pal Gianluca Vacchi (their host for the vacation) rode brown horses.

At one point during the afternoon, the 35-year-old Fast and Furious 7 actress was spotted looking at pictures on her camera. Efron stood beside her, his hand around her waist as he leaned in close to peer over her shoulder.

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The newly hot-and-heavy duo were also photographed dirty dancing and making out at the Billionaire Club in Sardinia, just days after they were spotted kissing on a boat off the coast.

"Zac and Michelle have great chemistry," a source previously told Us Weekly of the sexy pair, who met a few years ago and have been friends ever since. "They have a lot to talk about, a lot in common."