“Babies running our life..@smarthouse26 @billheuisler,” he wrote.
The Just Friends actress, 40, and Oosterhouse welcomed their first child via gestational carrier.
“One month ago today, Dec. 26th our amazing beautiful daughter came into this world. Feeling so grateful to have her in my arms… after years of fertility struggles I give thanks today to our kind, loving surrogate for carrying her,” the new mom recently captioned an image with her baby girl.
On New Year’s Day, Smart and Oosterhouse announced their daughter’s arrival.
“First football game for these two (not quite) giants. Go Big Blue! #nygiants,” the Gone Girl star, 43, captioned the image of his kids watching the New York Giants play the Philadelphia Eagles.
The actor’s husband David Burtka also posted a photo from the game.
“A ice cream cart at a football game?!? Yes, anytime!!! Thanks,” Burtka, 41, Instagrammed the image of NPH and the twins getting a sweet treat.
On Halloween, the Harris-Burtkas posed for another fabulously festive photo.
“Hooray for Halloween! #Marilyn #Groucho #Chaplin #JamesDean @dbelicious,” NPH captioned the image of their old Hollywood-themed costumes that included Marilyn Monroe, Groucho Marx, Charlie Chaplin and James Dean.