What cancer does Colleen Hoover have?

Writer and producer Colleen Hoover has revealed that she's receiving treatment for cancer.

Taking to Instagram stories on Monday, the author and producer behind "It Ends With Us" shared a selfie and wrote "Second to last day of radiation! I wish I could blame my hair and facial expressions on Texas Oncology but they've been great. Hope you never need them, but highly recommend them." 

However, the famed romance and thriller author did not say  what kind of cancer she is being treated for or how long she has undergone treatment. 

Hoover gave some insight into her cancer journey in a Facebook post on Friday, in which she explained that results from genetic testing told her the cancer did not "come from family genes" and that it "also didn't come from the two main causes of the cancer, which are HPV and excessive hormones."

"This means it was more than likely environmental/lifestyle, which is lack of exercise, poor diet and stress," Hoover wrote. "I'm happy and grateful to be alive but I hate vegetables. I hate when I have to get off the couch. I hate sweating."

She said, "If you see me at the gym, don't even tell me good job. If you see me at a restaurant eating grilled chicken and drinking water, I’m probably real mad about it."