Credit: Jeffrey Mayer/WireImage

Giuliana Rancic had an announcement to make during a Monday morning appearance on The Today Show -- but it wasn't the one she or anyone wanted or expected.

Instead of a happy pregnancy announcement, Rancic, 37, told Ann Curry: "I have early stage breast cancer."  The E! News host and Giuliana and Bill star made the frightening discovery back in August, as she was preparing for her third attempt to get pregnant through in vitro fertilization.

Rancic explained that her doctor sternly insisted that she get a mammogram before going through with the third IVF treatment. (The pregnancy hormones could "accelerate the cancer," Rancic recalled her doctor as saying.)

The star, who said she has no family history of breast cancer, "wasn't prepared to get a mammogram until i was 40 years old," she admitted. "I never in my wildest dreams expected anything to be wrong."

When the hospital called a few days later to tell her the shocking news, Rancic admits she was immediately "sobbing...It was like the world just crashed around me."

But a visibly emotional Rancic assured fans, "I will be okay, because I found it early. I'm doing surgery this coming week, and then I go to radiation for six and a half weeks."

At her side throughout the ordeal is husband Bill Rancic, 40. "Bill is unbelievable," Rancic gushed. "He lets me cry when I want to cry. He just lets me feel what I want to feel."

And the spouses of four years are determined to continue in their attempts to conceive once Giuliana's medical isseus are resolved. "I'm not gonna give up," she said. When she does get pregnant, "That baby will have saved my life," she mused. "There's some master plan. Now I know that [God] was looking out for me."

She urged all women to get tested for breast cancer. "I think a lot of us think we're invincible," she said. "We have to start putting ourselves on the to do list."