The 64-year-old actress has survived ovarian cancer nine years ago but received the news that she had breast cancer several weeks ago, reported People magazine.
"Sorry for the long silence. I was diagnosed with breast cancer two months ago and am recovering from a double mastectomy," Bates tweeted. "After much consideration, I underwent a double mastectomy.
Luckily, I don't have to undergo radiation or chemo. My family call me Kat because I always land on my feet and thankfully this is no exception," she said.
The veteran actress is looking positively to the future, saying, "My doctors have assured me I'm going to be around for a long time.
I'm looking forward to getting back to work doing what I love to do." Having appeared in films such as 'Titanic' and 'PS I Love You', Bates won the Academy Award for 'Misery' (1990).
More recently she has appeared in such films as 'The Day the Earth Stood Still' and 'The Blind Side', as well as TV series 'Six Feet Under' and 'The Office'. Emmy-nominated this year for her role as the feisty Harriet Korn in 'Harry's Law', Bates earned a second citation for her guest slot on 'Two and a Half Men'.