The family of five are pictured in the garden of Anmer Hall. George and Charlotte stand behind their parents, while Kate holds Louis in her arms.
Despite the adorable photo being shared thousands of times, there's a sweet detail we'd missed - until now. Three-year-old Princess Charlotte is actually wearing her big brother's blue cardigan.
George first wore the cardy to the Queen's 90th birthday in 2016, when he was the same age Charlotte is now: