Giuliana and Bill Rancic cannot wait for their first child to arrive.

"On the plane to Denver!! Baby watch has officially started!!" Bill, 41, tweeted on Monday. The couple is welcoming a baby thanks to a gestational surrogate.

He later tweeted,"Heading out for a hike with @GiulianaRancic here in Colorado. Can't go too far. Waiting for that call any day now!"

Last month, Bill told US Weekly that although he and Giuliana, 37, have homes in Chicago and Los Angeles, their son will "be born in Colorado," which is where their surrogate mother currently lives.

"We're going to go from Colorado to Chicago and then spend September and October in Chicago. And then we'll come back to the West Coast," Bill told US Weekly magazine.

"Everyone is pumped!" Bill said. "Not just our family but so many people. We're so lucky. So many people have been pulling for us and following our journey. This has all been magical for us."

Giuliana is "over the moon," Bill said.

"At the end of the day, whether you have a baby naturally, through adoption, through surrogacy, it's your baby. You're going to love that baby and that's all that matters," Giuliana said on the "Today" show, just a few weeks before confirming they had a child was on the way.

Giuliana has much to celebrate: her 37th birthday was on Friday, she has a new edition on the way and her contract with "E!" was extended through 2015.

But things haven't always been so good for the married couple of five years: Giuliana endured several failed IVF attempts, a miscarriage and was diagnosed with just last year, Giuliana underwent a double mastectomy after being diagnosed with breast cancer last year.

Giuliana and Bill told "E! News," they plan on trying for a second child once Giuliana's clear of the cancer treatments in five years.

"Five years puts me at 42, and a lot of people have kids at 42. So I'm definitely going to try again," she said.