Prince Harry will have a "problem" at the Coronation because the Windsors "don't forgive", former royal butler Paul Burrell has claimed.
Harry's attendance will see him appear in a public setting with King Charles, Queen Camilla, Prince William, Kate and the rest of his family for the first time since he lambasted the royals in his memoir, Spare.
It will also be the first time he has been pictured with the Windsors since the funeral of his grandmother the late Queen.
Harry criticised Charles' parenting, said the King was jealous of Meghan and Kate, and accused William of physically attacking him in his tell-all book, which was published in January.
He also branded Camilla "dangerous" and accused her of sacrificing him on her own "personal PR altar".
Last week, Buckingham Palace announced that Harry would be attending the Coronation, but Meghan would be staying behind in California with Prince Archie and Princess Lilibet.
Archie turns four on May 6, the same day the Coronation is taking place at Westminster Abbey.
And according to Burrell, a former butler of the late Princess Diana who also came in for criticism in Spare, Harry will get a "cold" reception from his royal relatives.
He said: "Harry's got a problem because he’s going to have to sit amongst family who he’s pushed under the bus and criticised and what kind of reception is he going to get?
"A very cold and icy one because the Windsors don’t forgive, they do hold a grudge.
"The family do push people out on the margins if they don’t conform and follow the party rules. The King has laid down the rules and Harry should follow them.
"It's the least he could’ve done, to do his father a favour and come to the coronation, even if he is by himself.
"Meghan has a great excuse not to come because it's Archie’s birthday on the coronation day, isn't that wonderful?
"She's got a birthday on the weekend of the coronation so she’s going to have to stay behind, isn't she."
Meanwhile, Charles' dilemma over Harry and Meghan is something he is experiencing the same as the late Queen, according to Burrell.
Speaking on behalf of Spin Genie, he added: "I feel sorry for the King, he has to walk a very strange tightrope, thinking about what will the people say on one hand because he’s King and on the other hand, what do I feel as Harry's father.
"So now he's witnessing what the Queen had all her life, this dilemma of splitting family and people because you can’t always do both and the Queen found herself in dilemmas sometimes between family and the people.
"When you're monarch you really have to put the people first and this is going to be a hard lesson for the King and he's not had this problem in the past because he hasn't been monarch but now the weight is fully on his shoulders."
