Bush, 27, made the announcement Tuesday morning on the "Paul & Young Ron Mornings" radio show, which airs in South Florida. "I have a little one on the way," he said. "We're pretty excited. We haven't found out if it's a boy or a girl yet."
He added: "We can't wait. It's the opportunity to bring in a new life and raise a child and I think that's the most special gift to a man and to a woman. So I look forward to it and to building a family."
Bush added jokingly to the radio hosts, "I'm hoping for a boy, because if it's a girl I'm going straight to the gun shop" to presumably fend off teenage suitors several years down the road.
Mom-to-be Avagyan, who has performed as a guest dancer on "Dancing With the Stars," was born in Armenia and began dancing at age 11, according to her biography for the touring production "Ballroom with a Twist." She began training in ballet three years later, and moved to the United States in 2001. She and partner Evgeniy Nazarov won the 2010 Rising Star award for Latin Dance at the 2010 U.S. National Professional Championships.
Bush dated Kardashian after the two were introduced at the 2007 ESPY Awards by Arizona Cardinals backup quarterback Matt Leinart, Bush's former teammate at USC. Kardashian told "Access Hollywood" in January 2009, "Matt introduced me to the love of my life and we will always be grateful."
The couple broke up six months later, but got back together a day after the marriage of Kardashian's sister Khloé to Lamar Odom in September 2009. They then broke up a final time the following March.