Meghan Markle will be on her husband’s arm as he attends his best friend’s wedding.
Prince Harry, 33, and his wife are expected to be there, as are Kate Middleton and Prince William.
Kate and William are thought to be flying back from their holiday in Mustique to attend.
William is also good friend’s with Charlie, an his older brother Thomas was one of William’s ushers at his wedding to Kate.
Many will be looking forward to be seeing what the two royal Duchesses wear.
Charlie van Straubenzee, 29, is a close friend of Prince Harry’s.
So close, in fact, that he was the Duke of Sussex’s best man at his wedding to Meghan.
Charlie is said to have given a cheeky speech at Harry’s reception at Frogmore House.
Photographer Tim Rooke revealed the news that Harry would be Charlie’s best man on 4 August via Twitter.
He wrote: “Unfortunately I will be missing the wedding of Charlie Van Straubenzee and Daisy Jenks where Prince Harry will be best man on August 4th in Churt, Surrey as I will be on the beach. Can’t do everything!’”
The date is also Meghan’s 37th birthday, and she will be spending it by Harry’s side.
Harry and Charlie met at Ludgrove Prep School in Berkshire, and have been close friends every since.
Charlie is marrying his partner Daisy Jenks, 27, who is a videographer.
She runs a business with her sister, working in the UK and Europe.
Daisy was also a guest at Meghan and Harry’s wedding and was snapped sitting in the front pews chatting away to fellow guests.
This is not the first wedding Meghan will have attended with Prince Harry.
Meghan attended the wedding of Celia McCorquodale in Stoke Rochford, Lincolnshire.
She was criticised for the ill-fitting blue print dress she wore on the occasion.
Celia McCorquodale is the younger daughter of the Princess of Wales’ sister Lady Sarah McCorquodale, and Harry’s cousin.
Meghan Markle wore a £600 striped shirt to Wimbledon with Kate Middleton recently.