Olivia Culpo suffers from endometriosis.

The 28-year-old model has revealed she has been diagnosed with the long-term condition, in which tissue similar to the lining of the womb grows in other places, such as the ovaries and fallopian tubes.

Endometriosis can often cause painful cramps, especially during periods, and Olivia took to social media to let her fans know she was experiencing ''excruciating pain'' as a result of her condition.

She wrote on her Instagram Story: ''I've never publicly said this before but I have endometriosis. Aka the most excruciatingly painful cramps/periods. Anyone else reading this have Endo? No fun. (sic)''

After revealing her diagnosis, Olivia's fans flooded her comments with supportive messages, with many saying they also have the common condition.

She added: ''I can't believe that a lot of you also suffer from endometriosis. It is so not fun, very painful.''

The model then urged anyone having ''painful periods'' without an endometriosis diagnosis to see a doctor, as the condition can impact someone's ability to have children.

She said: ''The thing I'm gonna say about endometriosis that I just think is really important is if you are having very painful periods and you are not being diagnosed with what you think could be endometriosis, definitely do your research because if you don't discover that you have this, it could get in the way of your fertility. You could have tissue growing in areas that you really shouldn't have that would interfere with maybe getting pregnant some day, your eggs could be getting damaged.

''Definitely go to your doctor if you have painful periods. Painful periods are not normal. You just want to make sure that everything is ok if you did want to get pregnant. You just never know. You don't want to wait too late, so I want everyone to take that seriously.''