Meghan Markle and Prince Harry will reportedly miss Prince Charles’ second 70th birthday celebration at the Buckingham Palace next month.

According to Vanity Fair, this is because the Duke and Duchess of Sussex will be in Australia for their first overseas tour. More specifically, Camilla Parker Bowles is helping to organize a birthday celebration for her husband on Oct. 25. The gathering will be attended by Prince William, Kate Middleton, and the other members of the royal family.

Invitations to the bash have been sent out last week. The event will be held to acknowledge Prince Charles’ commitment to, and patronage of, the arts over the past couple of years. The party will be produced by David Whelton OBE and directed by Greg Doran, and more.

“It’s going to be a very special night and Charles is very much looking forward to it. Harry and Meghan can’t be there because they will be overseas. It’s why they’re so keen to be at the garden party for Charles back in May,” a source said.

The Duke and Duchess of Sussex delayed their honeymoon for a few days so that they could celebrate Prince Charles’ birthday at the garden party in the Buckingham Palace. But since their 16-day tour of Australia, New Zealand, Fiji, and the Kingdom of Tonga will wrap up at the end of October, they won’t be able to make it to the future king’s second celebration.

Prince Charles’ actual birthday is on Nov. 14, and he will have another huge party at that time. His mom, Queen Elizabeth II, will be organizing a grand celebration for her eldest son.

Latifa Yedroudj, a journalist for Express, said that the Queen will be the one paying for all of the expenses for Prince Charles’ party. Some of the guests will include Bowles’ family, European royalties, and more. Michael Fawcett, Prince Charles’ personal aide, has been tasked to oversee the proceedings.