Buckingham Palace and a spokesperson for the Duke and Duchess of Sussex confirmed the news, saying Meghan would stay at home in the U.S. to look after the couple's two children.

Their eldest, Archie, turns four on the same day as King Charles' coronation.

"Buckingham Palace is pleased to confirm that The Duke of Sussex will attend the Coronation Service at Westminster Abbey," the palace spokesperson said.

"The Duchess of Sussex will remain in California with Prince Archie and Princess Lilibet."

Charles will be crowned in a ceremony that dates back 1000 years, surrounded by foreign heads of state and dignitaries.

But the participation of his youngest son had been in doubt after the 38-year-old heavily criticised his family in a book and documentary series.

Harry and Meghan stepped down from royal duties in 2020 and moved to California, saying they wanted to forge a new, independent life, free of the scrutiny of the British press.

They agreed with the royal family that they would not take part in any future official royal events or tours, and they have only been seen in the United Kingdom on a handful of occasions since they left, including for the funeral of Queen Elizabeth, who died after a 70-year reign.

With AAP.