We know Prince William and Prince Harry will be there, but will Prince Charles attend Princess Diana’s statue unveiling? Well, according to a new report, the Prince of Wales will not be joining his sons at a ceremony in honor of his late ex-wife—and his reason for skipping the event may have to do with some “regretful” memories.

The 72-year-old royal reportedly wants to avoid any painful emotions at the tribute for the Princess of Wales, whom he divorced a year before her tragic death in 1997. Their divorce came amid Charles’ years-long affair with Camilla Parker Bowles, whom he went on to marry in 2005. All these years later, Charles still finds the thought of attending Diana’s tribute “terribly difficult,” according to an insider who spoke to the U.K. Times.

“These moments have the potential to resurface old wounds, and it brings back memories for him; happy, sad, regretful,” the source told The Times in a report published on Sunday, June 27. “Since Diana’s death, he has felt it’s best to keep those memories to himself and leave his sons to it.”

The ceremony is set to take place on what would have been Princess Diana’s 60th birthday on Thursday, July 1. While their father won’t be joining them, both Prince William and Harry are expected to attend. The Duke of Sussex arrived in the U.K. ahead of the unveiling ceremony on Friday, June 25, according to PEOPLE.

It was previously revealed that Harry’s wife, Meghan, would not attend the memorial ceremony after welcoming their second child, Lilibet “Lili” Diana on June 4. Instead, Meghan is expected to remain at home in Montecito, California with her son Archie and daughter Lili. Duchess Kate, meanwhile, is also expected to skip the event. Daily Telegraph associate editor Camilla Tominey revealed to Express on Thursday, June 17, that the Duchess of Cambridge may not attend in order to give Harry and William some space for “reconciliation” amid their ongoing feud.

“We’ve never really been told that family is going to be included in this thing, we know this is the reunion for the brothers on what would have been Diana’s 60th birthday on 1st July,” Tominey told the U.K. site. “Never any suggestions that the Cambridges would attend along with Prince William and equally, that Meghan and the children would attend with Harry.”