Prince Harry and Meghan Markle
Then Prince Charles and Camilla Parker-Bowles, Queen Elizabeth, Meghan Markle and Prince Harry. Photo by: Getty Images/Tolga Akmen Getty Images/Tolga Akmen

Prince Harry and Meghan Markle might not make it to King Charles III's coronation on May 6 following news that they failed to confirm their attendance before the RSVP deadline.

The couple reportedly missed the April 3 deadline to RSVP and their representative, according to the BBC, also said last week that "there was no update on whether they were attending."

The Duke of Sussex received an email invite to attend the coronation in London's Westminster Abbey. But he and Meghan Markle remain undecided if they will attend the ceremony or not. Royal experts claimed that they have a valid reason if they choose not to be there because May 6 also falls on their son Prince Archie's fourth birthday. They might decide to remain in California to celebrate his milestone instead of having an awkward reunion with the royal family and face the British public's scorn.

But their hesitation has caused a "headache" for organisers, according to The Daily Mail Royal Editor Russell Myers. He told Sky News Australia that the Duke and Duchess of Sussex "haven't sent back their invitation reply" even after the RSVP deadline.

But he thinks that the couple will probably be given "a bit more leeway than the average person attending the coronation."

He also addressed rumours about the couple's demand to be part of the lineup on the Buckingham Palace balcony saying that King Charles III "had already decided that they wouldn't be appearing on the balcony" as it is reserved for working royals and their respective families.

These include Prince William and Kate Middleton, and their children Prince George, Princess Charlotte, and Prince Louis. Princess Anne will likely also be there and Prince Edward and his wife Sophie. This means no Prince Harry and Meghan Markle and no Prince Andrew, who Myers said is still in "exile" following his sexual abuse scandal. He said the public will see King Charles III's "version of a slimmed-down monarchy" from the appearance on the Buckingham Palace balcony.

Prince Harry and Meghan Markle allegedly sent a list of demands to attend the coronation. Aside from the balcony appearance, they also want their children Prince Archie and Princess Lilibet, to be part of the festivities amid claims that they were not invited. It is said that the couple also insisted that there will be a celebration of some sort for Archie's birthday. But all these claims remain unconfirmed by the couple.

In January, the Duke of Sussex expressed his doubt on whether he will attend his father's coronation. He told ITV's Tom Bradby during a promotional interview for "Spare" that a "lot can happen between now and then."

Yet despite his silence on the coronation, Prince Harry paid a surprise visit to London on March 27 to attend the preliminary hearing of his privacy case against Associated Newspapers Limited (ANL), the publisher of The Daily Mail. He reportedly requested to meet his father while in the country but the latter was "busy." He also did not get to see Prince William because he was away.

The speculation on whether Prince Harry and Meghan Markle will attend King Charles III's coronation continues to be a subject of contention among royal experts. Royal reporter Ephraim Hardcastle said that if the duke were to attend he would not be expected to bow to his stepmother, Queen Consort Camilla, whom he accused of leaking stories to the British tabloids in his memoir. Meanwhile, others claimed that His Majesty would want his family to witness his coronation given that it is very much a family affair also. Thus, he would want Prince Harry and Meghan Markle to be at the ceremony.