Jennifer Aniston and Gerard Butler: Undeniable chemistry on screen and off. (Photo courtesy of Sony Pictures Entertainment)

Gerard Butler hauls off a struggling Jennifer Aniston and stuffs her unceremoniously inside the trunk of a car. Moments later, a frazzled Aniston pops back up and smiles.

Despite shooting a rather rough scene for their latest starrer, it seems pretty obvious that America’s favorite friend and Sparta’s hunky noble king get along on the set of “Bounty Hunter.”

But more than that, what’s gotten the media tongues wagging are photos of Aniston and Butler all cozy and happy off the set.

The are-they-or-aren’t-they couple was recently seen together at the Golden Globes where Butler hammed it up for the cameras and Aniston just beamed while huddled close to the hunk on the red carpet.

Talking to “Access Hollywood,” Aniston reportedly said that Butler was “the most unpretentious guy” and that they had “so much fun together” while making the movie.

Aside from being “the most lovely and sort of self-deprecating (guy),” she also said that they both “had each other’s backs.”

Butler was also among the friends who joined Aniston for her 41st birthday celebrations in Los Cabos, Mexico this past week.

But aside from just partying at her reported $9,000-a-night villa in Cabo, San Lucas, it was said that the trip to Mexico was also a sort of “humanitarian holiday” for the famous bunch—which, aside from Aniston and Butler, included pals Courtney Cox, Sheryl Crow and Jason Bateman.

Apparently, Butler put it in her head that her coming to Mexico all the time—it is reported to be Aniston’s favorite holiday destination—could actually help drive up the image of the city among tourists, which is said to be hurting over reports of swine flu and drug trafficking. Indeed, the locals survive on holiday revelers spending money in Mexico’s beautiful places.

Aside from fun in the sun, reports also had it that Aniston also squeezed in a little promotional work at the launch of Farita dolls, sold with the help of the resort they stayed at to raise funds for an orphanage in the northern city of Tijuana, which she also reportedly visited.