Archie and Lilibet to join Harry and Meghan at party to celebrate major milestone for Duke of Sussex

No members of the Royal Family are expected to attend the event in the US.

The Duke and Duchess of Sussex's relationship remains strained with senior members of the Firm.

Meghan Markle received no public acknowledgement of her birthday from the Royal Family last month.

The Duchess of Sussex turned 43 on August 4 and celebrated the birthday with Prince Harry.

It comes less than two weeks after the Sussexes celebrated another birthday in Montecito.

Meghan's mother Doria turned 68 earlier this month and spent time with her grandchildren to mark the occasion.

The Duchess of Sussex is known to have a very close relationship with her mother, who attended her royal wedding at Windsor Castle in 2018.

Doria often looks after her grandchildren Archie, five, and Lilibet, two, when the Sussexes perform public engagements.

Doria featured in Harry and Meghan's Netflix series and discussed the moment she learned about her daughter's romance with the prince.

Meghan's mother said: "When she told me, we're on the phone and she says, 'Mummy I'm going out with Prince Harry'. I started whispering 'Oh my god!'"

LATEST ROYAL NEWS:

• James Middleton issues statement after Princess Kate's major health update
• Queen Camilla and King Charles make their feelings clear after Kate's major health update
• Prince Louis and Prince George's voices heard in rare moment during emotional video message
  

Doria added regarding meeting Prince Harry: "I remember when I first met him too, a 6’1 handsome man with red hair, really great manners.

"It was just really nice and they looked really happy together, like he was the one.

"Once it was announced that they were together it seemed kind of like a novelty."