Jeff Vespa / WireImage 1 / 6
Jeff Vespa / WireImage 1 / 6

The first rule of BFFs: Don't doggie paddle in the same dating pool. But that's what the rumor mill claims Courteney Cox has done to pal Jennifer Aniston with her "Cougar Town" co-star Josh Hopkins.

On Tuesday, an itty-bitty bikini-sporting Courteney, 46, was photographed frolicking on a St. Barts beach with the actor, 40, who was briefly linked to Aniston back in September (the dating whispers were denied all around).

Cox, who separated from David Arquette in October, shared the sun-and-surf time with 6-year-old daughter Coco, who looked to be having a ball with her mom and Hopkins.

Not surprisingly, the cozy scene has led to whispers of a hot-and-heavy hookup, which the co-workers moved quickly to quash.

"The relationship is strictly platonic," a rep explains to People, "and they are away with a group of friends on vacation."

Adds a "Cougar Town" spy, "Courteney and Josh are great friends. There's definitely nothing going on there."

The actress is "close to her co-stars," another source echoes to Us. "She's been like that since 'Friends.' But there's nothing more going on."

Cox has previously denied persistent chatter linking her to another co-star, Brian Van Holt, and in general seems wishy-washy about getting back into the dating scene.

"I have no desire right now," she recently explained to Harper's Bazaar (read the interview here). "I'm not saying never. It just seems weird."

Courteney's Caribbean getaway comes on the heels of her affectionate gushing over Arquette during their joint promotion of the forthcoming "Scream 4."

"Oh my God, I'm so proud of him!" she enthused to "Extra" of her estranged, rehab-graduating hubby. "Best he's ever looked! He's so cute that I'm like, dude, I don't understand. Really?! Why are you that cute right now?"

David, for his part, has made it clear that he's open to reconciling.

"I want her to be happy," he told Oprah last month. "I'd love for it to work out. … We truly love each other with all our hearts. I know that I'll be with her my whole life."

RELATED VIDEO: Courteney and David's adorable interview

RELATED: Courteney's bikini time in Hawaii

RELATED: Courteney and David go flower shopping

Read more Hot Gossip