Judy Blume. (Wikimedia Commons)

Best-selling author Judy Blume is battling breast cancer.

The Superfudge writer announced in a blog post on Wednesday she underwent a mastectomy following her diagnosis in June.

In the entry, she writes, "The biopsy report came back a few days later while I was with my (gynaecologist) in her office (a long standing appointment).

"It was good that I wasn't alone and that she, who has been my doctor for seventeen years, could explain it to me. Very early. Very small. Well differentiated. All good news. But it was invasive ductal carcinoma."

Blume is now recovering at home in New York City with her husband George at her side, and assures fans her condition is improving.

She adds, "Now it's one month post surgery - I'm still in NY and feeling stronger every day, walking a couple of miles in the park each morning and going out to early dinners with George. Have seen movies and a couple of plays, as you know if you follow me on Twitter. I'm able to read again without falling asleep. Which doesn't mean I don't need a nap every day."