Neil Patrick Harris, David Burtka's Twins Turn Four, See Their Birthday Photo!

Gideon and Harper turn four! Credit: Courtesy Neil Patrick Harris, Bruce Glikas/FilmMagic via Getty

Happy birthday, Gideon and Harper! Neil Patrick Harris and husband David Burtka spent the weekend celebrating their twins' fourth birthday — and the proud dads shared an adorable photo of their happy kids via Twitter.

The cute, blonde-haired duo looked beyond excited on the morning of Sunday, Oct. 12, as they prepared to tear the wrapping paper off their fourth birthday presents with their two doting dads.

"Happy 4th birthday, Gideon and Harper," Gone Girl star Harris captioned the snap. "I can't believe that you used to be tiny baby things. And now, this."

Harris and Burtka have had a lot of celebrating to do recently. In September, the couple, who had been engaged since 2007, officially tied the knot during their wedding ceremony in Italy.

Talking on The View after the event, Harris explained he and Burtka wanted to marry for the sake of their children.

“I think when our kids got to the age when they were having reasonable conversations where they’re asking lots of ‘why’ questions, then it seemed [important] to be able to have a real clear-cut [identity] of who their daddy is — that he’s my husband, it was easier than partner or boyfriend,” he said.