Prince William and Kate Middleton attended Prince Philip's Birthday!

Kate Middleton and hubby Prince William attended yet another royal shindig Sunday, Prince Philip's 90th birthday celebration.

Arriving in a vintage Rolls-Royce, the Duke and Duchess of Cambridge headed in to St. George's Chapel for William's grandfather's commemorative service, with Kate strolling down the walkway in a blue brocade frock coat and nude LK Bennett heels, according to People, And since there was a light rainfall, William made sure to hold an umbrella over Kate's head until they entered the chapel.

Stepping out of a vintage Rolls Royce in a blue brocade frock coat and her trusty, nude LK Bennett heels, Catherine made the short walk through the rain to the side entrance of St. George's Chapel, where a service was held in honor of Philip's service to Great Britain and the Queen.

Prince William was by her side, holding an umbrella over Catherine's head until they reached the entrance, where they mingled with Prince Harry and other guests, including the Queen, who wore a sky blue royal crepe coat with white silk print dress and matching Angela Kelly hat.

There also attended, Prince Charles and his wife Camilla, the Duchess of Cornwall, William's uncles, the Duke of York and the Earl of Wessex, and his aunt, the Princess Royal, William's cousins Princesses Eugenie and Beatrice.