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Before heading to Cannes, Brad Pitt took his boys to see Star Trek over the weekend.

Pitt, 45, Maddox, 7, and Pax, 5, went to morning showing of the sci-fi flick on Saturday in Huntington, Long Island -- near the home the family has been staying while Angelina Jolie films thriller Salt in NYC and Washington, D.C.

Check out Angelina Jolie's best action movie roles.

"Brad drove the boys to the cinema complex and spent two hours watching the show with his boys," a witness tells Us. "They arrived around 10:30 a.m. and walking in with all the other moms and dads with their children.

"No one seemed to notice them. Then one lady spotted Brad, and words soon got around they were inside the theater," the witness adds.

See adorable photos of Brad and Angie with their kids -- including the twins!

"The boys had popcorn and sodas," the onlooker continues. "And when they left at the end, both Maddox and Pax seemed really excited and clearly enjoyed the movie very much." reports the brothers were re-enacting scenes from the movie in the parking lot.

Last month, Pitt took his boys to Niagara falls for the day with his parents.

He premieres his Quentin Tarantino flick, Inglourious Basterds, at the Cannes Film Festival tomorrow.

Check out photos of stars at the Cannes Film Fest.

Jolie attended a child soldiers trial in the Netherlands today.