Prince Harry, Meghan Markle and their children are on their way to London after departing Los Angeles, it is believed.
The California-based couple, who quit as frontline royals in 2020, will join members of The Firm to mark 70 years since the Queen was crowned.
They are expected to attend trooping the colour tomorrow in London - but are unlikely to appear on the balcony with working royals.
Instead it is thought they will watch on as spectators, while Prince Andrew is not expected to attend at all.
It will be the first time the 96-year-old monarch will meet great-granddaughter Lilibet, who was named in her honour.
Harry and Meghan's daughter will turn one on Saturday, and is making the trip alongside three-year-old brother Archie.
Harry has been given a "cast-iron guarantee" that he will be given taxpayer-funded police protection, having previously launched legal action against the Home Office.
It is the first time Meghan has returned to the UK since the couple quit royal life.
Since then relations between them and the family have been fraught, with their bombshell interview with Oprah Winfrey seeing them level allegations of racism against an unnamed royal.
The couple also claimed to have been cut off financially from Harry's relatives, while the Duke of Sussex claimed Prince Charles and Prince William were "trapped" in their roles.
Earlier today The Mirror reported that it is still unclear exactly which Jubilee celebrations they will attend - and if their young children will join them.
It is thought they will attend the St Paul’s Cathedral thanksgiving service on Friday and potentially the Jubilee pageant on Sunday.
Celebrations kick off tomorrow with Trooping the Colour, but the Queen has ruled that only working members of the family will be allowed on the Buckingham Palace balcony for the traditional fly-past.
A security source told Mail Online that Prince Andrew, who recently reached an out-of-court settlement with sex abuse accuser Virginia Giuffre to prevent a court showdown, will not be present tomorrow.
Camera crews from Netflix, which the couple have a £100million production deal with, followed them during the Invictus Games.
But a source said: “There has been further contact between the Duke and members of his family, but any talk of them planning to cause a scene or detract from the Queen’s celebrations is nonsense.
“They are here to see family and enjoy what will undoubtedly be an incredible moment in history.”
Meanwhile, other sources close to the couple said it was “ludicrous” to suggest they would bring the Netflix cameras with them, adding: “They aren’t even bringing a press team. It’s all very low key.
“Whoever is being hysterical needs to have a cup of tea and calm down.”
Their arrival in the UK comes after Harry received “cast-iron assurances” that his family will be protected by specialist police when he touches down in the UK today.
Harry and Meghan are said to be flying in with their own personal security detail but will become the Metropolitan Police’s responsibility when they land.
It will be only the second time Meghan has returned to the UK in more than two years since the couple dramatically quit their royal roles in 2020.
