The creator, writer, star and director of HBO series Girls now faces surgery.
On Saturday (5 March), spokesperson Cindi Berger revealed that Golden Globe winner Lena had been taken to an undisclosed hospital that morning.
The statement read: "Lena Dunham has been very public with her personal bouts with endometriosis. This morning, she suffered from an ovarian cyst rupture and has been taken to the hospital.
"Lena will be undergoing surgery at an undisclosed hospital. We thank you for you understanding and hope that Lena's privacy will be respected."
Comedienne Lena has previously been very open about her battle with endometriosis, a painful disease that occurs when tissue that normally grows inside the uterus grows outside of it.
The condition can also lead to infertility, and 10 per cent of the world's female population suffer from it.
Lena, 29, had recently cancelled appearances for the upcoming series of Girls, telling fans she had been going through a "rough patch" with her health.
She said her body and her doctors had let her know "in no uncertain terms" it was time to rest up.
Lena wrote on Facebook: "Hey Beloved Pals, I just wanted to let you know that, while I am so excited for Girls to return on Feb 21, I won't be out and about doing press for the new season.
"As many of you know I have endometriosis, a chronic condition that affects approximately 1 in 10 women's reproductive health.
"I am currently going through a rough patch with the illness and my body (along with my amazing doctors) let me know, in no uncertain terms, that it's time to rest."
Get well soon Lena!
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