The American Idol alum, 35, and Angel Reed welcomed their first child, Malena James, on Thursday at 11:06 p.m. She weighed 6 lbs., 11 oz., and measured 19 inches long.
"Sometimes Christmas comes early and we're so lucky to get the greatest gift a few days early," Maroulis tells PEOPLE. "Angel and I are thrilled to welcome our perfect baby girl into the world today. Mom and baby are healthy and I couldn't be more excited to ring in 2011 this way."
The new parents met last year while they were starring in the Broadway musical Rock of Ages.
Maroulis shared with PEOPLE his excitement over impending fatherhood last July.
"It's a beautiful thing," he said at the time. In preparation for being a dad, he said he was, "just living every day right now, trying to do good work and provide for family long term – so I'm looking forward to the road ahead, definitely."
Maroulis is currently reprising his Tony-nominated role as rocker Drew in the Rock of Ages national tour.