Katy Perry isn't shy -- and that goes for whether she's putting Taylor Swift on blast or talking about her skin issues. The "Swish, Swish" singer even used to be a Proactiv spokesperson. "You would think I would be the most confident person, but the most confident person still has their moments," Perry said in a commercial for the brand. "A lot of my insecure moments related to my face and to my skin problems." In the commercial, she points to her mouth, nothing that she had blemishes around it. "I wanted to hide," she said.

In an interview with Refinery29, Perry said that even though she no longer works with Proactiv, she still uses their products, citing their Skin Smoothing Exfoliator as one of her faves.

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"Royals" crooner Lorde might only be 20 years old, but she's wise beyond her years. In a Twitter post, she pointed out the difference between two photos of herself from the same day -- one had been touched up and one hadn't. "I find this curious -- two photos from the same day, one edited so my skin is perfect and one real. Remember flaws are ok :-)"

She also snapped a pic of herself treating her skin and shared it with her 5.7 million Instagram followers. "In bed in Paris with my acne cream on," she wrote in the caption.

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The "La La Land" actress told Refinery29 that she used Accutane, a powerful prescription acne med. "I'm actually pretty interested in skin care, because I had bad hormonal acne when I was 17, and they put me on Accutane for it," she said in the interview. After two months on the Accutane, I went off of it, and since then, my skin, my mouth, my lips, my eyes are all so dry."

Fun fact: After going off Accutane, Stone said she got stress acne -- and that it was airbrushed out of her breakout (see what we did there?) movie, "Easy A." "I realized how debilitating and embarrassing it can be to have cystic acne," she said. "So I'm really interested in the biology of what makes up acne and how to work on it from the outside, too."

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Like Perry, "Dancing with the Stars" pro Julianne Hough was also a Proactiv spokesperson back in the day. In an interview with the Beauty Bean, she described her acne as "horrible." She elaborated: "You know, again, you try to tell yourself that you're fine and it's all good -- and you really should be fine -- but it definitely affects you, so you want to do what you can to make you feel good. Not to worry so much about what everybody sees, but to do what makes you feel good on the inside."

In a blog post on her own website, Hough recommended the Proactiv Skin Purifying Mask as an overnight blemish treatment. "When it comes to pimples, you want to have a strong defense, and this tube of unicorn cream is one of the biggest reasons!" she wrote. "It works really hard while you're sleeping and when you wake up, you won't believe the difference."

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Ah, we have yet another Proactiv spokesperson in our next celeb, "Glee" graduate Naya Rivera. "I had really bad skin for awhile earlier this year," Rivera told People while on the set of a Proactiv photo shoot. "It sort of just came out of nowhere. It was like adult acne, and I was like, I've had great skin my entire life. How am I dealing with this now at 24?"

Rivera continued that she was embarrassed to go to work and be on camera every day when she had pimples erupting all over her face. That being said, Rivera noted that her "Glee"costars were super-supportive. "I would always go around and talk about it," she told People. "It was a point of insecurity for me. But I'm glad I got it fixed, I'll say that."

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