GREEN BAY—Secrets are hard to keep in Hollywood, but this one was kept quiet for quite a while.

Five Packers players are in the upcoming movie “Pitch Perfect 2,” set to be released this summer, and the news got out on Thursday as the trailer was released.

Clay Matthews, David Bakhtiari, Josh Sitton, T.J. Lang and Don Barclay (along with Aaron Rodgers’ younger brother, Jordan) appear in the trailer, which briefly shows them in a night-club scene with Matthews getting the sleeves of his tuxedo jacket torn off as he poses and flexes his muscles.

“We’re all A-list celebrities now,” Matthews joked.

The players talked about the movie project with the media on Thursday after practice. Their involvement began with a tweet from Bakhtiari to Alexis Knapp, one of the stars of the original “Pitch Perfect” from 2012.

A big fan of the movie, Bakhtiari has made his teammates fans of it as well, and he took a shot in the dark on Twitter about getting him and his offensive linemates into the sequel.

“A lot of determination by Dave to set the whole thing up – determination-slash-desperation, because he was at it quite a bit trying to get a hold of the producers to get us in the movie,” Lang said. “Shockingly, they actually let us in after all his desperate tweets and phone calls and emails. It was fun.”

Added Matthews: “We have to thank him for his creepiness. He had to do a lot of lobbying, but he came through, and more power to him.”

Turns out the producers got a kick out of the fact that a bunch of Packers players were fans of the first flick, so they cast the group in a scene. As soon as OTAs wrapped up in June, the players flew down to Baton Rouge, La., for four days of shooting.

They even had to fill out actors’ union paperwork and got paid, but that was far from the motivation.

“We probably would have paid to be in the movie, to be honest with you,” Lang said.

Lang added that the Packers do a little singing and dancing within the musical competition that’s part of the plot, but the rest of the details of their scene is being kept under wraps.

“It was a piece of cake,” Sitton said of the filming, tongue planted in cheek. “We were definitely fish out of water at first. Then we kind of got into our groove, and it turned out to be pretty good.”

How good, and what song do they sing?

“It was a shock. We got a good laugh out of it,” Matthews said. “It was funny to see 300-pound plus men singing … said song.”

The players described it as four long days of filming, and it was an eye-opening experience to see the attention paid to costumes, make-up and the like.

The early reviews on the players’ appearance in the trailer were all positive.

“I think it’s fantastic,” Bakhtiari said. “I’m hoping the movie is just as good.”

The players brought back a free T-shirt for Head Coach Mike McCarthy, which he said was “big stuff” in his household and has made the rest of his family jealous.

The Packers’ involvement might have remained secret until the movie’s release had the producers not wanted to use them in the trailer to help promote the show.

But the cat’s out of the bag now.

“I was a little leery of it at first,” Matthews said. “But this stuff doesn’t happen every day, so when it did come up, you obviously have to jump at it.”