Lili Reinhart has been diagnosed with endometriosis

Lili wrote on Instagram: "Last week, I was officially diagnosed with endometriosis following laparoscopic surgery.

"Last year, I saw a urogynecologist and was diagnosed with interstitial cystitis. I was told there was no cure-and no lasting relief-for my symptoms. Three hospital visits. Multiple urologists and gynecologists. And not one of them seriously considered endometriosis as the underlying cause of what I was experiencing.

"It wasn't until I worked with two different pelvic floor therapists that the word endometriosis was even mentioned to me as a possible source of my pain."

Lili was unconvinced by her initial diagnosis and the actress actually had to push to have an MRI scan.

The Riverdale star is now glad that she "listened" to her body and Lili has pledged to "continue advocating for others" in the coming years.

Lili's post continued: "I pushed for an MRI on my own, which led to a diagnosis of adenomyosis. From there, I met with an endometriosis specialist who helped me decide that laparoscopic surgery was the next step I wanted to take-while, at the same time, another gynecologist told me I "probably didn't have endo" and should just go on the pill.

"I'm glad I trusted my body and listened to my gut and will continue advocating for others to do so. (Endometriosis is an extremely misunderstood disease, leaving often a 4-11 year gap between symptoms and a definitive surgical diagnosis. It's estimated 1 in 10 people with uteruses have endo according to the World Health Organization.) (sic)"

Lili also posted a hospital selfie on her Instagram Story, revealing that she felt "validated" by her diagnosis.

She said: "I don't remember taking this horrible photo. But I think I wanted to capture a moment of post-surgery validation. The second I saw my doctor I asked, 'did you find it?' And he said, 'We found endo.' And I felt so validated and relieved that I chose to listen to my body and pursue this surgery. (sic)"