"There [were] a lot of people with us, but we're the only ones you see [in the photos]," Hopkins, 40, told Access Hollywood of their group getaway earlier this month. "They just frame us two so it's a story. It's not true."
Hopkins says he was hesitant at first to go on the trip, but it was his TV boss that encouraged him to go.
"I wanted to go to the beach," he said. "[Courteney] said, 'You should come with me to St. Barts.' I was like, 'Maybe, you know, I don't know.' And then [Cougar Town]'s creator Bill Lawrence was like, 'If I'd go anywhere, I'd go to St. Barts.' "
Both Cox, 46, and Hopkins, who play couple Jules and Grayson on the ABC comedy, are not strangers to on-set romance rumors. After separating from husband David Arquette in October, Cox was rumored to be dating her Cougar Town co-star Brian Van Holt (both denied the reports). Hopkins was also rumored to be dating Cox's Friends cast mate Jennifer Aniston shortly after she guest-starred on Cougar Town's Season 2 premiere, but the two said they were just friends.
Hopkins admitted there are worse things in the world than being linked to a beautiful woman.
"It's not like a terrible story to have out there," he said. "It's not like I'm upset about it. I mean, she's really hot. But it's just not true."