STAGE TUBE: Giuliana & Bill Rancic Announce Pregnancy on TODAY

Giuliana Rancic learned she had breast cancer last October while she was preparing to undergo fertility treatments. But as she and husband Bill announced on TODAY this morning, her cancer treatments won't delay their family expansion: They're welcoming a baby into their home, thanks to a gestational carrier.

"It was pretty much one of the best moments of my life, if not the best moment of my life," Giuliana told Ann Curry about learning that one of the embryos they had banked prior to her diagnosis had resulted in a pregnancy. "It was just another world, on another level."

The difference between a gestational carrier and a surrogate parent is that biologically the child is Bill and Giuliana's; the gestational carrier brings the baby to term, but is not genetically related to the child in her womb.

The baby is due in late summer, but they would not reveal the child's gender, which they say they know.

Giuliana, who co-hosts "Fashion Police" on E! and who shares a reality show with Bill ("Giuliana & Bill" on Style Network) explained that her baby's carrier lives "out of state" and is married with two children. The couple wants to guard her privacy and not cause additional stress during her pregnancy, so they did not go into many more details about her, though they say they visit "every month" and appear to have a good relationship with her. Giuliana calls the carrier her "my baby mama."

"This was our last stop," said Bill. "This was it. We had those two embryos that we had banked prior to learning about the breast cancer, and with the medicine she was on (which meant Giuliana will have to wait years before trying to personally get pregnant), this was our last effort. The prayers were answered."

Both smiling parents-to-be were upbeat, and talked about turning "negatives into positives." And Giuliana seemed particularly grateful: "The more you focus on the positive, the more you are grateful for the good things in your life, the more good things come to you. I've really seen that. I have a great husband ... and I have a baby on the way. What more can I ask for, really?"

View the couple's exciting announcement on this morning's TODAY show below!