The official account of Charles and his wife, Camilla, Duchess of Cornwall, also shared photos of Harry.
"Wishing The Duke of Sussex a very Happy Birthday today!" the post reads.
In addition, The Royal Family official account, which provides updates about the queen and other members of the royal family, posted photos of Harry from throughout the years.
Harry's birthday follows his wife Meghan Markle's 40th birthday in August and the birth of their second child, daughter Lilibet, in June.
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In July, Lilibet was added to the royal family's line of succession. She is eighth in line for the throne, following her brother, Archie, 2, and Harry, who is sixth in line to succeed the queen.
Harry and Markle moved to Los Angeles in March 2020 after stepping down as senior members of the royal family. The couple said in an interview with Oprah Winfrey this year that racism partly drove them from the United Kingdom.
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