Next it was her turn to ogle him at the lifeguard tryouts.
Entertainment news outlets quickly followed, citing both their cozy antics at the award show and sources who claimed they had instant chemistry on set.
In an image of the pair taken on-set, Rebecca could be seen gazing into Zac's face as he looked directly at the camera.
"A pic is worth a thousand words," he wrote in the caption.
Okay, so that sounds pretty cut and dry—but it was technically a kiss on the cheek, which could totally happen between friends.
The costars, who are currently in the midst of a very strenuous international press tour for their upcoming blockbuster (which, it begs mentioning, involves spending a whole lot of time together), both attended the recent MTV Movie & TV Awards and marked the occasion by posting a seemingly innocent photo on Instagram.