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Veteran actress Kathy Bates battled ovarian cancer almost a decade ago and is now opening up about why she originally kept her diagnosis a secret.

"I was advised to [do so]," Bates, 63, told Anderson Cooper in an episode of his daytime talk show "Anderson" airing Thursday. "I was contracted to go into a movie at that time, 'Little Black Book' with Brittany Murphy, who I miss very much. My doctors at the time, they had to get insurance approval and all of that so I was very quiet about it and had to go back to work right away."

"Little Black Book" came out in 2004. Bates went public about her cancer battle in 2009, saying on NBC that she had been in remission for more than five years.

On "Anderson," Bates said she also had personal reasons for keeping her diagnosis quiet.

"Nobody else really knows what you're going through except another cancer patient," she said. "Even though your family's supportive and surrounds you, I just got to the point where I would go to chemo by myself and just really go through it on my own."

Having toughed it out in secret, Bates said she would be more open about her fight if the cancer returned.

"I admire people who have been open, like Melissa Etheridge and women I see walking around facing it without wigs and all of that stuff," she said. "I think I'd be more courageous next time."

Bates isn't the only actress to recently open up about hiding a cancer diagnosis. "Modern Family" star Sofia Vergara told Health magazine why she kept her thyroid cancer a secret when she was diagnosed in 2000.

"I didn't want publicity because of that," she said. "Having cancer is not fun. You don't want to deal with anything else while you're going through it."