Despite a challenging year for himself and his entire family, Princess Kate included, sources say Charles has "a levity about him and a sense of joy."

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 celebrated his birthday on Thursday by opening two new food distribution hubs - one in person and the other virtually.