"I love them already, but I need them to come out so I can really shower them with love," the Sugar Ray singer told People. "I can't wait to meet them."
McGrath, 42, and Kingsland, 37, are expecting a boy and a girl in May. The couple got engaged on New Year's Eve after dating on-and-off for 16 years.
"We love the idea of getting married on 10/10/10," McGrath told People, "but the twins might have another idea."
McGrath will serve as the host of Fox's Don't Forget the Lyrics! next fall.