Baby boy Rancic is nearly here!

On Monday, Bill Rancic wrote a happily frantic Tweet about the imminent birth of his and wife Giuliana's first child, a baby boy, via gestational surrogate.

"On the plane to Denver!! Baby watch has officially started!!" the reality star and entrepreneur, 41, wrote.

Bill told Us last month that although he and Giuliana, 36, have homes in Chicago and Los Angeles, their son will "be born in Colorado," which is where the woman carrying the couple's child currently resides.

PHOTOS: LOL! The Rancics take Us' parenting quiz

"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 explained.

And, when the time comes, the new family's ourney from Colorado to California will be a road trip! "I've got a tour bus taking us from Denver to Chicago," Bill explained.

PHOTOS: Bill and Giuliana's love story

"Everyone is pumped!" Bill added. "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."

VIDEO: The baby's emotional first ultrasound

The happy news comes after years of struggle for the spouses of five years, who endured several failed IVF attempts, a miscarriage and a breast cancer battle for Giuliana.

Mom-to-be Giuliana is "over the moon," Bill said.

This article originally appeared on Giuliana, Bill Rancic Prep for Baby's Birth!