@PSchwarzenegger / Twitter 1 / 3
@PSchwarzenegger / Twitter 1 / 3

Patrick Schwarzenegger is following in his father's footsteps in more ways than one! In addition to becoming an actor -- he plays a fraternity brother in the comedy "Grown Ups 2," in theaters July 12 -- action star Arnold Schwarzenegger's son is bulking up. The 19-year-old showed off his buff body by posting a shirtless picture of himself on Twitter on June 7.

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Flexing his muscles and showing off his six-pack abs, the college sophomore wrote, "Early morning pump! Who is getting into shape for summer? Gonna gain 7 pounds this summer."

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Long before he starred in hit movies like "Conan the Barbarian" and "The Terminator," Arnold gained fame as a professional bodybuilder. Now 65, the father of five earned the Mr. Universe title at age 20 and went on to win the Mr. Olympia contest seven times.

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Before his fall semester begins, Patrick will spend his summer shooting his second feature film, "Dear Eleanor," in Denver. "Very happy and excited to work on my next film," he tweeted on May 30. Directed by Kevin Connolly, the movie also stars Jessica Alba, Luke Wilson and Isabelle Fuhrman.