Prince William had a royally happy first Father's Day as a dad, playing in a charity polo match while wife Kate Middleton and adorable son Prince George showed their support from the stands.

Middleton, dressed casually in a striped long-sleeved T-shirt, skinny jeans, sunglasses atop her head and flat shoes, held and played with the little prince as she cheered for her hubby on the field.

George, who turns 1 next month, also practiced his walking -- with the help of mama Kate -- and crawled around in the grass, tugging on 32-year-old Middleton's pants.

"You know George -- wriggle wriggle wriggle," a polo spectator told Us Weekly. "He was adorable."

"He was grabbing one of the polo mallets at one point when Kate joined in with the divot-stomping during a break. Kate seemed a bit nervous to let go of him though. She said, 'He's really fast," the witness added.

At one point, baby George, looking as sweet as ever in a pair of pink overalls, a white shirt and little black booties, also kicked a mini, baby-sized soccer ball.

The baby's uncle, Prince Harry, also played in the match alongside older brother William, 31, but on the opposing team.

Yesterday's Royal Charity Polo event raised money for the various charities. It was held at Cirencester Park Polo Club in Gloucestershire, England.

Meanwhile, on Saturday, the royal family celebrated Queen Elizabeth's 88th birthday at a parade honoring the milestone. William, Harry and Middleton were all there, as were Prince Charles and wife Camilla, duchess of Cornwall, and the queen's husband, Prince Philip.