George, Louis and Charlotte smile big in unseen royal photo with dad William editors

It's all smiles for the Cambridge children! 

The British Army helped ring in Prince George's sixth birthday on Monday, July 22nd with a previously unseen photo of the royal. The snapshot, which was shared to Twitter, shows George standing alongside sister Princess Charlotte, father Prince William and baby brother Prince Louis at the King Power Royal Charity Polo Day two weeks ago. 

The family is joined by representatives of the army and Domhnall, the Wolfhound mascot for the Irish Guards, who is as big as Charlotte! 

"The Army In London, including @irish_guards Wolfhound mascot Domhnall, is wishing HRH Prince George a very happy 6th birthday today. Our Soldiers are always on duty, ready to serve! #PrinceGeorge" the army wrote on Twitter. 

The royal tot reportedly celebrated his big day on a family trip to the private island of Mustique for the second year in the row. One of the photos released by the palace was captured by the Duchess of Cambridge during their trip.

It's been rumored that Kate and William are also throwing him a magic-themed bash at Kensington Palace with his school friends upon their return from holiday. 

“The Duke and Duchess of Cambridge have gone all out to organize a birthday party for George,” said an insider to Us Magazine. In addition to a magician, the fun-filled day will also include cupcakes, ice cream and a bounce house!

For more on the royal's big day, watch the video above.