"We all know it can be hard to reach acceptance and self love but it is so important," Willis, the 30-year-old daughter of Bruce Willis and Demi Moore, wrote in the caption. "But it has been one of the greatest and most rewarding things I have done. I love the me I see when I look in the mirror. I urge you all to take a step back and remind yourselves that we are beautiful no matter how we feel about our imperfections. They make us who we are."
The post was shared in partnership with Aerie. Willis wrote that for every fan who shared a photo of themselves with the hashtag #AerieREAL, the brand will donate $1 (up to $50,000) to the National Eating Disorders Association.
Willis and her younger sisters Scout and Tallulah have all been open about facing personal demons. In July 2017, Willis opened up about celebrating six months of sobriety.
"It's not something I planned on but after the long journey of getting here I can honestly say I have never been more proud of myself in my entire life. Thank you all for the love and support and remember to be gentle with yourself," she wrote at the time.
In 2017, Tallulah, 25, also got candid about her struggles with an eating disorder.
"3 years ago I was a malnourished string bean with aches that echoed throughout my soul," Tallulah wrote at the time, alongside an older photo of herself. "However the internal cries to tend my most blistered and deep wounds repeatedly fell on deaf ears. I did not value myself, my life or my body and as such I was constantly punishing for not being enough. Self annihilation fueled with medicating left me a shell, and the world on mute. I was hoisted from my hole, (one so deep I was certain we were nearing the Earths magma core) on the backs of powerful human beings that I will forever be indebted too, and on that day my life was gifted back to me."
More recently, the Willis family has celebrated happier times. In August 2018, the family gathered to celebrate Willis' 30th birthday. Willis also took part in the first season of Fox's The Masked Singer.
Last month, Willis appeared on the Mother's Day episode of Martha & Snoop’s Potluck Party Challenge, where she recalled how Moore reacted to her first tattoos.
“She definitely freaked out the first time I showed her I have tattoos,” Willis said. “I have tons. I’m getting a lot of them removed actually so I probably should have listened to her!”
Willis has a role in Quentin Tarantino's Once Upon A Time In Hollywood, which hits theaters on July 26.
Photo credit: Michael Tran/Getty Images