Kate Middleton and Prince William Shared a Cheeky Photo for King Charles's Birthday

He's not a regular king, he's a cool king.

King Charles isn't a regular king, he's a cool king—and all the proof you need is in the birthday snapshot shared by his son Prince William and daughter-in-law Kate Middleton. 

On Thursday, the Prince and Princess of Wales led the birthday tributes to Charles on social media with a cheeky photo posted to their Instagram Story. "Wishing a very Happy Birthday to His Majesty The King!" they wrote alongside an image of Charles, who just turned 76, wearing a light beige suit accessorized with a pair of stylish sunglasses and a lei made of colorful flowers around his neck.

In addition to the Wales family, the official royal family's Instagram page also shared a new portrait of Charles, dressed in his usual suit and tie, in honor of his birthday. 

William and Kate's photo was from King Charles and Queen Camilla's royal tour of Australia and Samoa last month, in which the monarch addressed his mortality amid his ongoing cancer battle while attending a traditional Ava ceremony in the village of Siumu.

According to the Daily Mail, the king capped off the trip with an emotional speech and got uncharacteristically frank about his health and age, telling the audience that he would love to return to the island of Samoa again, but wasn't sure if it would happen in this lifetime.

"I shall always remain devoted to this part of the world and hope that I survive long enough to come back again and see you," Charles said, adding, "We shall take away with us, I promise you, very special memories of our time here. We thank you for our wonderful gifts."