The Duke and Duchess of Sussex will join senior royals at a major platinum jubilee event within hours – but royal-watchers shouldn’t hold out too much hope of too many other sightings of the California-based royals during the Queen’s special weekend.

Prince Harry and Meghan Markle are back in Britain with their children this weekend – the first time the entire family has visited since the couple sensationally quit as working royals more than two years ago.

Harry and Meghan will join other family members at a national service of thanksgiving at London’s St Paul’s Cathedral on Friday.

The Queen, however, won’t be there. Buckingham Palace announced late on Thursday that the 96-year-old monarch would skip the church service after experiencing “discomfort” at the Trooping the Colour parade.

“The Queen greatly enjoyed today’s birthday parade and flypast but did experience some discomfort,” a palace spokesman said.

“Taking into account the journey and activity required to participate in tomorrow’s national service of thanksgiving at St Paul’s Cathedral, Her Majesty with great reluctance has concluded that she will not attend.”

Harry and Meghan’s absence from the palace balcony for Thursday’s parade, which kicked off the four-day platinum jubilee weekend, was also noticeable.

By the Queen’s decree, only “senior working royals” appeared with her on the balcony – Prince Charles with wife Camilla, the Duke and Duchess of Cambridge and their three children (youngest son Prince Louis was a noted scene-stealer), and the Earl and Countess of Wessex and their children.

The Duke and Duchess of Sussex were relegated to a much lower-profile viewing spot with lesser royal relatives. They were snapped – Meghan in a navy frock and broad white hat, Harry sans military uniform – watching the festivities from the Major General’s Office, but took no part in the official ceremony.

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The office, which once belonged to the Duke of Wellington, overlooks the palace’s parade ground.

Other senior royals, including the Duchess of Cambridge and Duchess of Cornwall, also watched part of the parade from the same room. It is believed to be the first time Kate Middleton and Meghan have met in person since the Sussexes left Britain in 2020.

According to London’s Telegraph, their low profile while back in Britain so far is all part of a carefully choreographed return.

“This jubilee is all about demonstrating what working royalty is all about. They will be made prominent by the media but none of the non-working royals are actually going to be that prominent,” a royal insider told the newspaper.

“The distinction has been drawn between institution and family.”

The ‘senior working royals’ on the Buckingham Palace balcony on Thursday. Photo: Getty

Beyond Friday’s service at St Paul’s it’s not yet known if Harry and Meghan will feature in any other jubilee events, including Saturday’s Party at the Palace and the final pageant on Sunday. But it appears unlikely.

“I’m not convinced you’re going to see a lot of them. The Queen has been clear on it all,” a royal insider told the Telegraph.

“That’s the reality of where they are now, and it’s about the Queen doing the final part of her job, signing it off with her seal of approval in a very clear and public way.

“It’s about Prince Charles, the Duchess of Cornwall, the Duke and Duchess of Cambridge and their children being front and centre of the monarchy. It is her showing what she sees as the future of the family.”

Elsewhere, however, the Queen is widely expected to meet the Sussexes’ daughter, Lilibet. She turns one on Saturday, and had not yet any of her royal relatives before this weekend.

Her big brother, three-year-old Archie, was last in Britain when he was just six months old.

Harry and Meghan are believed to be staying at Frogmore Cottage, their official British residence. It is on the grounds of the Windsor Castle estate – where the Queen is now permanently based.

-with AAP