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Patrick Schwarzenegger is only 18 years old, but he's already following in his famous father's footsteps in the acting profession. One of his latest projects is a public service announcement to promote Lady Gaga's Born This Way Foundation and ET went behind the scenes of his photo shoot.

"The overall campaign is like a movement to spread kindness," Patrick said during a break from shooting. He also said the campaign comes at the right time -- with kids returning to school in a process that can be nerve wracking and scary -- and described the PSA's message as "promoting bravery and acceptance."

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Gaga's Born This Way Foundation has teamed up with Office Depot's Back-to-School Kindness Campaign -- allowing students to purchase gift cards, post-it notes, bracelets and other items containing positive messages. Office Depot gave $1 million to the Born This Way Foundation and is also donating 25 percent of sales from campaign-related products.

Patrick said he was excited to get involved in the campaign with Lady Gaga, whom he admires for her anti-bullying efforts. "She was bullied and obviously some people were cruel and mean to her when she was growing up. But I think the world and society accepted who she was. And now her level of fame and success shows other kids that they can really be who they are."

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