Sophie Monk has been hospitalised after discovering a painful diagnosis.

Sophie Monk has revealed she is one of the 700,000 women in Australia living with endometriosis.

And just like so many women who have the painful condition that can affect fertility, it took her decades to find out.

The actress and TV host shared what appears to be the moment she was diagnosed via a video posted to her Instagram Stories on Monday.

In it, the 38-year-old is lying in a hospital bed post-surgery while a doctor is discussing her surgery.

“We did find some endometriosis, but not much,” the Monash IVF doctor can be heard telling her.

Sophie had someone film the conversation. Image: Instagram

Confirming the diagnosis to her followers, Sophie captioned the clip: "So many women live not knowing they have endometriosis. If you have annoying cycles. You should ask your doctor."

It's wise advice considering there's an average delay of diagnosis for endometriosis of seven years, according to Endometriosis Australia. One reason it is so under-diagnosed is that symptoms - such as heavy, painful periods - are normalised.

The former Bachelorette also shared a video of herself unconscious as doctors prepare her for surgery, captioning the clip: "Best sleep I’ve had in years."

Endometriosis is a disease where the tissue that normally lines the uterus grows outside of it, which can include the ovaries and fallopian tubes. Surgery to remove some of this misplaced tissue can be a form of treatment. While many people with endometriosis do conceive naturally, the condition can negatively affect fertility.