Celebrity chef Sandra Lee announced on “Good Morning America” on Tuesday that she was diagnosed with breast cancer a month and a half ago. The Food Network star will undergo a double mastectomy this week after a lumpectomy failed to remove all of the cancer.

“I didn’t even cry, I was stunned,” Lee said. “You know, and that’s just how fast life turns. It turns on a dime.”

Lee was diagnosed with DCIS (ductal carcinoma in situ), a common noninvasive cancer contained within the milk duct, which can become invasive if left untreated, during a routine mammogram. She said the cancer has not spread.

“And so I said, ‘OK. If I’m going to have a mastectomy, am I supposed to just get one done?’ Both the radiologist and the doctor said, ‘You’re a ticking time bomb.’ And they both said, ‘You need — I would just get them both done,'” Lee said.

The 48-year-old TV personality, who’s hosted “Sandra’s Money Saving Meals” and “Semi-Homemade Cooking with Sandra Lee,” also said she’s glad she didn’t wait to turn 50 to get a mammogram, as recommended.

“My first focus is to get the surgery done and recover,” she added. “After that I’ll be all over my sisters and nieces to get tested. I don’t care that my niece is 23 years old.”