RUB-A-DUB! Two hotties in a tub have sparked a gay furor!

Hollywood hunks Jon Hamm and Daniel Radcliffe share a bathtub in a British TV miniseries, and now the stud-muffin screen stars are quickly becoming gay icons.

The “Mad Men” dreamboat, 42, and the “Harry Potter” wizard, 24, play the same character years apart in the Sky Arts period drama “A Young Doctor’s Notebook.”

In one scene, the two are filmed in a bathtub with Daniel as the younger doctor addressing his future self, as played by Jon.

“It’s a very homoerotic scene,” a crew member who worked on the set told The ENQUIRER. “Just the thought of Jon and Daniel splashing around naked in a tub together is a delicious fantasy for gay guys. They’re both gorgeous, and gay men love that neither of them has any hang-ups about appearing to be naked in a tub together.”

Both actors are straight. Jon lives with his longtime love, actress Jennifer Westfeldt, while Daniel has been dating actress Erin Darke.

But the photo of their on-set splash party is becoming a hot ticket on gay blogs.

“There is something so wrong, yet so right about Jon Hamm and Daniel Radcliffe in a tub together,” commented one reader on the gay website Queerty.

Referring to Hamm’s notoriety as one of Holly­wood’s most well-endowed actors, the source added: “The gays love them some Hamm, and the fantasy of him hooking up with Daniel is just too good to resist.”