Last week, the What About Us hitmaker, 38, posted a photo with 6-year-old daughter Willow at Kaaboo music festival in Del Mar, Calif.
The Family Portrait hitmaker turned 38 on Sept. 8.
“Happy birthday to my amazing wife @pink,” Hart wrote on social media.
He added: “Thank your for letting me be along for the ride all these years. I’ve watched you grow from a kid to an amazing woman and mother. Sorry that the sick kids kept us apart on your birthday, and I can’t wait to give you a birthday spanking! Love you.”