Julianne Hough is opening up about her experience with endometriosis. The 28-year-old actress and dancer was first diagnosed with the disease in 2008, and is now teaming up with the national campaign Get in the Know About ME in EndoMEtriosis to help raise endometriosis awareness. Endometriosis is thought to affect as many as 6.5 million women in the United States, but many people don't know much about it, which is one of the reasons why Hough was motivated to speak out.

"It's such a weird, awkward thing to talk about, and that's why we're here with this campaign, to bring awareness to women and also people around you—friends, colleagues, siblings," she tells Health. "You might not be the 'me' in endometriosis, but maybe someone around you is."

Endometriosis causes the endometrial tissue to migrate outside of the uterus. Symptoms can include painful periods, excessive bleeding, and pelvic pain that can be severe. But it's notoriously difficult to diagnose, and doctors often mistake endometriosis for pelvic inflammatory disease, irritable bowel syndrome, or just a bad case of PMS—which is what Hough initially assumed her symptoms were.

"I started having symptoms when I was 15, but didn't really realize that it was anything more than just being a woman," she says, telling us she would experience "really, really sharp" pelvic pains that became debilitating. "I'd have to stop for almost 30 seconds and just like, curl down for a minute."

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Women with endometriosis are more likely to experience pain on their periods, but symptoms can last longer, as well. "It was throughout the month, and I had really heavy bleeding for the whole month," Hough says. "It was really bad, but I thought, 'Oh, I'm just weird.'"

When she first moved to Los Angeles, Hough's roommate at the time had endometriosis and often spoke about it. But she didn't make the connection to her own symptoms.

"When she first said she had endometriosis, I was like, 'Oh, that sounds way too medical, I don't know what that means,' and it just went right over my head," Hough says. "Even though I was like, 'That kind of sounds like me, I have that too.'"

Hough was "properly diagnosed" in 2008 while competing on Dancing With the Stars, she says. In a 2008 interview with People, she described being hunched over backstage with abdominal pains so severe that “it felt like a knife was being stabbed in me,” she said. A hospital visit revealed endometriosis-related scar tissue that had spread to her appendix, which was about to burst. A week later, she underwent laproscopic surgery to remove scar tissue and her appendix. 

"It was sort of a relief to know that I actually had a name to the pain and that it wasn't just part of being a woman, and that I had to tough it out," she says.

Hough still experiences endometriosis symptoms today. To manage them, she focuses on eating well ("I'm not into a lot of acidic foods, and I don't really binge eat") and getting plenty of exercise. The actress is known for her love of fitness—she's been a professional dancer since age 15, has shown off her moves on Grease Live! and DWTS, and even has her own line with MPG Sport. "I definitely live with [endometriosis] every day," she says, and she admits it's not always easy to feel motivated on days when her symptoms are acting up.

"Sometimes I don't [work out] because it's too much," she says. On these not-so-great days, she likes to take a hot bath and turns to her trusty hot water bottle to ease cramps. "I call it the boiling baby because I hold it like a baby and I tend to, like, rock."

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Hough—who joins a growing list of public figures using their platforms to raise awareness for the disease, including Lena Dunham, Padma Lakshmi, Tia Mowry, the singer Halsey—hopes that by speaking out, she can help more women identify symptoms of endometriosis and visit their doctor for a diagnosis.

"Hopefully because of my story and being able to talk about it, people will hear it and be more aware that maybe they might have it," she says.

One of the reasons why this is so important to Hough is because being able to tell people what she's going through has made a big difference for her, she says.

"It's a relief, because if I'm in a photo shoot or on set doing something or I'm dancing, I can take a minute and have a break if I need to," Hough says. "I don't feel like I have to hide or push through the pain. I can take a second, because people understand and they know."

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She's also become the go-to person that her friends call for advice about their own menstrual pain.

"I'm kind of the girlfriend in my friend circle where they all call me when they're going through something, and are like, 'What do I do, this pain is so bad, I'm throwing up," she says. "Because I'm able to talk about it openly, people feel comfortable and understood."

What would Hough say to someone who just found out they were diagnosed with this disease? "Welcome to the club! You're not alone," she says. "We're here to support each other and empower each other. We're in this together."