The 4-year-old son of Prince William and Kate Middleton made headlines for his goofy antics during last year's Platinum Jubilee.
World of the first lady's attendance comes amid news that her husband will not be on hand for Charles' coronation next month.
A source tells ET that despite the rift, there was no slight as King Charles was not in town the same time as Prince Harry.
Harry was in London as part of a high-profile court hearing last week.
King Charles' coronation is set to take place May 6.
Preparations are underway for King Charles' coronation on May 6.
The coronation is set to be held on May 6.
The monarch's coronation ceremony is slated for May 6 in London.
Charles' coronation ceremony is slated for May 6.
Prince Harry made a surprise appearance Monday at High Court, and was also there on Tuesday.
England's new monarch isn't interested in giving handouts to his famous family anymore, it seems.
Queen Elizabeth died on Sept. 8. at the age of 96.
The couple has been invited to the May event.
Prince Edward got an unforgettable honor from his oldest brother on his 59th birthday.
