When Makena Brister and Shawn Arnold arrived on Santa Catalina Island just off the coast of Southern California on Saturday afternoon, they had one thing on their minds: the raunchy 2008 comedy “Step Brothers.”

The 22-year-olds stepped off their ferry in matching blue button-down shirts and argyle sweater vests, dressed to recreate the movie’s memorable poster of Will Ferrell and John C. Reilly, who star in the film as two middle-aged men that begrudgingly become family when their parents remarry.

The mixer is the emotional finale of the film, where the bickering step brothers finally come together to save the day after a bad Billy Joel cover band nearly ruins the event.

“This has been a dream since watching ‘Step Brothers,’” Ms. Brister said. “It’s our favorite movie, we watch it all the time.”

The couple traveled from Granite Bay, Calif., to attend the 10th year of the Catalina Wine Mixer, an event that was inspired by its fictional counterpart in the film, and which the Catalina Island Company decided to make real in 2015. The group owns about 11 percent of the island and is behind various efforts to attract visitors.