Although Prince Harry and Meghan Markle's children secured their royal titles of Prince and Princess, they are alleged to be without a metaphorical key to the castle: an invitation to King Charles III's coronation.

According to reports, both Prince Archie, 3, and Princess Lilibet, 1, have yet to receive an invitation to the coronation in May, per The Telegraph.

Since the release of Prince Harry's explosive memoir "Spare" in January, Harry and Meghan's inclusion at the coronation has been questionable. 

Last week, it was reported that the King had extended an invitation to the Duke and Duchess of Sussex, per The Sunday Times.

Meghan Markle in a printed dress holds Prince Archie as an infant as Prince Harry looks at them while in South Africa

Although months away, it has been reported that Prince Archie and Princess Lilibet have not received invitations to King Charles' coronation. (Pool/Samir Hussein/WireImage)

However, the Duke and Duchess have allegedly been given no information about whether their children are invited to the festivities.

The news of the apparent snub comes days after it was reported King Charles, Queen Camilla, Prince William and Kate Middleton did not attend the christening of Lilibet in California, per People.

"I can confirm that Princess Lilibet Diana was christened on Friday, March 3 by the bishop in the Episcopal Diocese of Los Angeles, the Rev John Taylor," a spokesperson for the Duke and Duchess of Sussex told Fox News Digital in a statement. 

A spokesperson for Buckingham Palace did not immediately respond to Fox News Digital’s request for comment on the reported absence. 

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Harry and Meghan are said to be deciding if they will attend the coronation, as friends revealed to The Telegraph that they have not given a decision to the palace. It was relayed to the couple that the inclusion of Prince Archie and Princess Lilibet would potentially be discussed if and when they accept the invitation.

With planning underway for the grand event, a royal source claims it's "always easier" to arrange for guests who choose not to attend an event rather than organizing last-minute additions.

Prince Harry in a blue button down shirt and black suit smiles with wife Meghan Markle in the Netherlands for the Invictus Games

Prince Harry and Meghan Markle have already received their invitation to King Charles' coronation. (Mark Cuthbert/UK Press)

When asked by a royal source if the Duke and Duchess's son and daughter were invited, they reportedly shared that the children are "very young."

A representative for the Duke and Duchess of Sussex as well as Buckingham Palace did not immediately respond to Fox News Digital's request for comment.

King Charles' other grandchildren from son Prince William and wife Kate Middleton are expected to attend, per The Telegraph. Prince George, 9, is expected to have a specific role in the ceremony, as the future monarch of Great Britain. Princess Charlotte, 7, will reportedly be in attendance, although the Prince and Princess of Wales are deciding whether their youngest child, Louis, 4, will be included.

King Charles III looks off to his right in a pin-stripe navy blue suit

The coronation of King Charles III is to be held on May 6. (WPA POOL)

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Even with an extended invitation to Harry and Meghan, the rift between the family is still prevalent. 

Just weeks ago it was confirmed that Harry and Meghan were asked to vacate their residence of Frogmore Cottage.