When Harry celebrated his 40th birthday in September, however, King Charles and Prince William both acknowledged his day with a social media tributes. Middleton even celebrated brother-in-law's milestone day with a phone call, a source told Express.

The British monarch turns 76 today, November 14, and to mark the occasion, his royal family sent him well wishes via social media—details here.

Prince Harry and Meghan Markle have remained silent on King Charles's birthday. The Duke and Duchess of Sussex have not sent a public message to the monarch on his 76th birthday. Earlier today, the Prince and Princess of Wales wished the King a happy birthday publicly on social media.