"He and his wife Christine are very happy and very excited about it," publicist Paul Bloch told PEOPLE.
Costner, 52, and handbag designer Christine Baumgartner, 32, wed at his ranch near Aspen, Col., in September 2004.
The couple met while golfing more than a decade ago, but didn't begin dating until they met again at a restaurant in 1998. Despite a brief split in 2002 and an almost 20-year age difference, the two are "like little kids together, really in love," close friend David Giammarco told PEOPLE at the time of their wedding.
