Rumer Willis explained to Us Weekly why she was so upset after being Photoshopped to appear thinner in a lookbook, saying it was "f---ed up" and "unacceptable." Credit: John Sciulli/Getty Images

Don't go down that road! Rumer Willis vented her frustrations to Us Weekly on Thursday, Oct. 23, about recently being photoshopped — without her consent — to appear thinner in a fashion lookbook.

"I was more frustrated," the Hollywood scion, 26, told Us at her event with Torrid in L.A. "I think I would have felt very differently if I was a model who was hired to be a part of the brand. I get that there are certain things they want to change or whatever. But, if you're hiring me to be a representative of your brand and you’re changing who I am — like drastically changing how I look [while] everybody knows how I look [by] taking away the muscle — I just thought it was odd, you know?"

Willis posed for Franziska Fox's spring 2015 lookbook (released last month) in super-sexy threads featuring cutouts and plenty of exposed skin. She mused of the photos: "If you have a zit or something on your face or a weird crease that you want to get rid of, don’t get me wrong: I’ll be the first to be like, 'Yeah, that looks weird.'" The editors behind her lookbook, though, "were trying like, to change my face and take the muscles out of my arms… It looked weird."

Willis told Us she was repulsed by the images as soon as the brand released them via Instagram. "My stylist told me about it and I was like, 'Well, that's f---ed up.' Then I immediately called my manager and said, 'You know, this is unacceptable, because that’s not what I want to put out in the world and what I want to represent anyway.'"

Despite the ever-mounting pressure in Hollywood to be thin and perfect, Bruce Willis and Demi Moore's eldest said the greatest goal is to remain true to oneself. "The ideal, you know, in this industry — all of the photos that you’re growing up as a little girl and seeing — are all Photoshopped and retouched. This idea that how you are is not okay [should] not [be] the case. You should be able to feel beautiful with no makeup on, completely naked, and feel totally stoked about how you look and no one should be judging you for anything."

Willis told Us where she gets this natural confidence. "A long time ago," she said. "I just had a moment where I realized that I could either choose to let other people’s perceptions and opinions about me define who I am and let that be how I define and value myself." Her way of dealing with it? "I don't give a crap," she told Us. "If you walk out of the house — even if you’re wearing a onesie or sweatpants or an evening gown — as long as you feel good about yourself, that's all that should matter."

After the Photoshop incident, Willis said plus-size brand Torrid approached her about a partnership. "I just thought it was so cool that there's a brand that’s so opening and welcoming to all people of different shapes and sizes," she explained to Us. "And this came at the perfect time."