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Sharon Osbourne underwent a double mastectomy when she learned she carried a gene for breast cancer, she told Hello! magazine in an article that hit newsstands this morning.

Although Osbourne, the wife of Black Sabbath front man Ozzy Osbourne, was not diagnosed with breast cancer, she was diagnosed with colon cancer in 2002, and said the experience prompted her to have both her breasts removed in a 13-hour operation.

"As soon as I found out I had the breast cancer gene, I thought, 'The odds are not in my favor'," Sharon told the magazine. "I've had cancer before and I didn't want to live under that cloud. I decided to just take everything off, and had a double mastectomy."

Osbourne had a foot of her colon removed in 2002 and underwent chemotherapy. Once she was in remission, she founded the Sharon Osbourne Colon Cancer Program at Cedars-Sinai Medical Center in California in 2004.

A new grandmother to her son Jack's daughter, Pearl, Osbourne told Hello! she didn't feel sorry for herself.

"For me, it wasn't a big decision, it was a no-brainer," she said. "I didn't want to live the rest of my life with that shadow hanging over me. I want to be around for a long time and be a grandmother to Pearl.

Click here to read more about the Osbourne family's woes.

Women who have the "breast cancer gene" have mutated BRCA1 or BRCA2 genes, according to the National Cancer Institute. Normally, the genes are tumor suppressors, but a blood test can reveal that they don't function properly.

A 2008 study published in the Journal of Clinical Oncology revealed that more women were choosing to have double mastectomies, removing both the breast with cancer and the other healthy breast. The study found that the rate of the procedure, called a contralateral prophylactic mastectomy, more than doubled between 1998 and 2003. Although the study author said the preventative surgery did not decrease cancer risk, women said they did not regret their decision to remove their healthy breasts.

Several other celebrities have opted for double mastectomies in the past, including Christina Applegate and Kathy Bates.

Applegate, 40, was diagnosed with breast cancer in 2008. She told More magazine last month that she originally had two lumpectomies, but when she learned that she had a mutated BRCA1 gene, she decided to have the more extreme surgery.

Bates announced in September that she was recovering from a double mastectomy after receiving a breast cancer diagnosis. Bates, an Oscar-winner, battled ovarian cancer in 2003.