The Dukes of Sussex and Cambridge will be separated by their cousin, Peter Phillips, as they walk behind the Duke of Ednburgh’s coffin on Saturday (17 April).
The plans may further fuel the rumours of a “rift” between the two sons of Prince Charles and the late Princess Diana.
Harry previously spoke about his strained relationship with his brother during the bombshell Oprah Winfrey interview with his wife, Meghan Markle.
So, why will Prince Harry and Prince William walk apart during Philip’s funeral, what has their relationship been like over the years - and do they speak now?
Here is everything you need to know.
Why will Prince Harry and Prince William walk apart at the funeral?
The decision to separate the two dukes at Prince Philip’s upcoming funeral was said to be the Queen’s.
Since Harry moved to the US with Meghan after the pair stepped down as senior royals, the brothers have not seen each other for a year.
A source close to Peter Phillips, Princess Anne and Captain Mark Phillips’ businessman son who will walk between William and Harry, told The Telegraph that he would “act as mediator”.
"Pete is very diplomatic and gets on very well with both William and Harry,” the source disclosed.
"Clearly there are still tensions between the brothers, and Pete will try to defuse the situation.
"As the eldest of all the Queen's grandchildren, he will take responsibility for ensuring there are no problems on the day."
William will walk ahead of Harry as the Duke of Edinburgh’s coffin is taken into St George’s Chapel.
The Queen signed off the plans for the funeral service on Thursday 15 April.
She is said to have ensured that nothing "detracts from what the day is about, commemorating the extraordinary life of her husband".
Were Prince William and Prince Harry close as children?
The brothers were tight-knit as children.
Photos from when they were growing up show their close bond, and they were often seen playing together.
When they grew up, both princes attended the same boarding school, Eton College.
After the tragic death of their mother Diana in 1997, their relationship became even stronger.
William, in a video from 2017, opened up about how the two were "uniquely bonded because of what we've been through”.
Despite the brothers pursuing different paths after leaving high school, they came back together to work in the military.
During their helicopter training in 2009, William and Harry shared a cottage, joking that it would be their "first and last time living together”.
Their bond seemed to remain strong, with Harry serving as William’s best man at his royal wedding to Kate Middleton in 2011.
After they were married, the Duchess of Cambridge started to attend events with William and Harry, with royal insiders revealing the three were close friends.
According to the 2020 book Finding Freedom by Omid Scobie and Carolyn Durand, Harry also doted on his niece and nephew and “always loved popping across the grounds of the palace to see Charlotte and George, bringing them gifts that included an electric SUV for his nephew and a tricycle for Charlotte”.
William then returned the honour of being best man at Harry’s wedding to Meghan Markle in 2018.
How did the royal ‘rift’ begin?
That same year, reports of a rift between William and Harry began to circulate in the media.
According to an anonymous source who spoke to Vanity Fair’s Katie Nicholl, much of the tension came after Meghan was introduced to the royal family.
Things reached boiling point during Christmas 2018, the source said, as Harry felt that William was not making a big enough effort to include his new wife.
"Harry felt William wasn't rolling out the red carpet for Meghan and told him so," said the source.
"They had a bit of a fallout, which was only resolved when Charles stepped in and asked William to make an effort.
"That’s when the Cambridges invited the Sussexes to spend Christmas with them.”
Then, the following year, Nicholl said that things became worse when William told Harry that he was concerned by how fast his relationship with Meghan had moved.
In the documentary Kate v Meghan: Princesses at War?, Nicholl explained: "I think what was meant as well-intended brotherly advice just riled Harry.
"Harry is hugely protective of Meghan. He saw that as criticism.
“He interpreted that as his brother not really being behind this marriage, this union, and I don’t think things have been quite right ever since.”
Was the relationship ever smoothed over?
Public speculation that things were not healthy between the two brothers increased throughout 2019.
Footage of the royals attending an Easter Sunday service together showed that William and Harry failed to speak to each other.
But in May that year, the situation was apparently smoothed over, with William and Kate reportedly extending an “olive branch” by going to Harry and Meghan’s new home, Frogmore Cottage.
And as the Duke and Duchess of Sussex welcomed baby Archie, William spoke publicly about being “thrilled” for the couple.
Yet Harry appeared to confirm the brothers’ rift despite that, during an ITV documentary about their royal tour named Harry & Meghan: An African Journey.
"Part of this role and part of this job, and this family, being under the pressure that it’s under, inevitably, you know, stuff happens,” the duke said.
“But look, we’re brothers, we’ll always be brothers. And we’re certainly on different paths at the moment, but I’ll always be there for him, as I know he’ll always be there for me.
He added: "We don’t see each other as much as we used to because we’re so busy, but you know, I love him dearly.
“The majority of this stuff [in the press] is created out of nothing, but you know, as brothers, you know, you have good days, you have bad days.”
For Christmas 2019, Harry and Meghan opted to spend the holiday with the duchess’s mum instead of with the rest of the royals.
A source told US Weekly that the decision was down to the “rift” between Harry and William.
Do William and Harry speak now?
Just when it seemed like their relationship was permanently damaged, in January 2020 there were reports that the brothers were working to put their differences aside.
That came only days before Harry and Meghan announced that they were stepping down as senior working royals.
After the bombshell decision, it was rumoured that the brothers managed to stay civil, speaking over a video call when Harry moved to LA with Meghan.
But during the shocking Oprah interview, the duke spoke about his relationship with his older brother and confirmed that it was still fractured.
He said: “I love William to bits. He’s my brother, we've been through hell together... but we were on different paths.
“The relationship is space, at the moment. And, you know, time heals all things, hopefully."
Also in the interview, Harry revealed that he believed his brother was “trapped” in the royal family, along with his father.
"I was trapped, but I didn't know I was trapped. My father and my brother, they are trapped. They don’t get to leave," he said.
Sources have said the interview has the potential to damage William and Harry’s relationship completely since there was already tension between the pair.
Four days after the chat was aired, William told reporters on Thursday 11 March he hadn’t yet spoken to his brother but that he plans to.
Some of the interview revelations were said to have upset the Duke of Cambridge.