With only three weeks remaining until King Charles' coronation ceremony, a series of complications have thrown the event's planning into disarray, according to a report by the Mirror.

Among the issues are the rehearsal exceeding its scheduled duration and the delayed RSVPs from Prince Harry and Meghan Markle, which have further hindered the planning process.

Royal aides are reportedly scrambling to finalize plans before the May 6 ceremony at London's Westminster Abbey, as several significant concerns remain unresolved.

A royal insider told the Mirror, "It's all very frantic, complete chaos, to be frank. There is a plan, which is supposed to be the blueprint of how the day should operate, but things are changing daily, which is causing massive headaches."

Another source described the planning process as coming "down to the wire."

"Everyone involved, including the King and Queen Consort, wants the event to be perfect, which is why everything is being done to make it so," the source added.

Royal aides are still awaiting RSVPs from the Duke and Duchess of Sussex for the coronation, despite invitations having been sent out weeks ago.

The unresolved issue of whether Prince Harry and Meghan Markle will attend the event has reportedly left the seating arrangement incomplete. The couple has not yet disclosed whether they will travel from their home in Montecito, California, to London for the occasion.

If they do attend, the Duke and Duchess of Sussex may face a "cold shoulder" from senior members of the royal family, as reported in a separate article.

Other concerns include confusion over the wearing of tiaras by female members of the royal family during a time when the Firm is cutting back on expenses.

Sources also revealed to the Mirror that King Charles and Queen Consort Camilla have been practicing their roles for the coronation in a "mock-up Abbey" constructed within Buckingham Palace in preparation for the event.

The Post has contacted Buckingham Palace for a statement on the matter.