Brothers Mike and Dave Stangle wore thoroughly bemused looks at Wednesday’s premiere of “Mike and Dave Need Wedding Dates” at the Arclight Hollywood, where Zac Efron and Adam DeVine portrayed the siblings in the raunchy comedy.

The Stangles originated the story in 2013 by taking out a Craigslist ad: “My brother and I are looking for wedding dates for our cousin’s wedding. We’ve been told by the bride that bringing dates is mandatory so we won’t ‘harass all of my friends all night and stay under control.’”

The ad went viral and the brothers published the book “Mike and Dave Need Wedding Dates: And a Thousand Cocktails” two years later. Fox’s movie, which opens July 8, makes the bride-to-be the sister of the brothers, rather than their cousin, and sets the wedding in Hawaii with Anna Kendrick and Aubrey Plaza portraying the dates.

“The movie is wilder than what happened to us, which was pretty wild,” Mike Stangle mused on the red carpet. “It’s surreal to be here.”

Efron sported frosted hair on the red carpet and referred to Mark-Paul Gosselaar’s character from “Saved by the Bell” by asserting, “Zack Morris is my hero.” The actor had a mini bro fest when he posed on the carpet with Devine, piggybacking him alongside his “Workaholics” co-stars Anders Holm and Blake Anderson.

Alice Wetterlund, who plays the brothers’ cousin, said she came away from the shoot last year with admiration for Efron’s comic chops, adding, “He embodies the character perfectly.”

UCB comedienne Mary Holland, who plays the maid of honor, said that it was a challenge to play a humorless character.

“I got to play the most normal person in the movie,” she said. “I’ve never been a maid of honor but I’ve got a good idea what an uptight one would be like.”

Jake Szymanski directed from a script by Andrew J. Cohen and Brendan O’Brien. Producers are Peter Chernin, Jonathan Levine, David Ready and Jenno Topping.

“Everyone in the movie is perfect,” said Szymanski as he started the screening.

The after-screening bash took place at 33 Taps, where several games of beer pong engaged attendees.