Harry and his wife Meghan Markle have both been invited to the ceremony, which will be held on May 6, however, there has been no confirmation on whether they will actually attend. Despite this, it is expected they will be there for the big day.
The Duke of Sussex is reportedly requesting a private apology from his father and brother Prince William before he will confirm his attendance at the coronation.
However, a royal expert believes Charles is unlikely to give Harry what he wants.
Nigel Cawthorne, author of Prince Andrew, Maxwell and the Palace told Express, "Meghan has, thankfully, kept her mouth shut lately. It's Harry wanting an apology that poses more of a threat to the coronation.
"But Charles knows he can't go around apologising to people - that's ridiculous. It's far beneath the King to do that."
Harry has previously refused to commit to attending the coronation unless Charles and William "sit down and talk about" the allegations he brought against the family in his record-breaking memoir Spare.
Claims Meghan not 'brave enough' to attend
Despite reports Harry will attend the coronation solo, royal author Victoria Arbiter told Sunrise the Duke will only attend if Meghan also goes with him.
"Relations are so sour, I don't think it would make any difference if Harry was there or not," she told the hosts. "Harry would probably like to have her with him just to have someone in his corner, but the coronation is not going to present an opportunity to build bridges and has the kind of conversations this family needs to have in order to move forwards and heal.
"It's possible Harry will breeze in, show up for the coronation ceremony and breeze out much in the way he did at the Platinum Jubilee.
"He kind of went to key events but he and Meghan missed the concert at the palace and they were out of town and on a plane before the pageant had even finished."
This comes as former royal butler Paul Burrell claimed Meghan is not "brave or strong enough" to return to the UK for the coronation.
He told Closer Magazine, "I don’t think Meghan’s brave or strong enough to be there – she’d had to look in the eyes of a family she’s pushed under the bus.
"But I think Harry may come alone, and she’s probably told him she won’t be able to be by his side with him if he does attend."
This claim was countered by Arbiter, who said Meghan is a "very strong woman".
"I think it's an extraordinary claim," she said. "You only have to look at Meghan's desire to take on the British press and even walk away from the institution of the monarchy to recognise that this is a very strong woman.
"The fact is she is a strong, independent woman and I do think she has shown immense bravery."
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