Peter Phillips has split from his partner Lindsay Steven after four years together, a source has confirmed to HELLO!
The King's nephew, 46, and his long-term girlfriend are understood to have ended their relationship a couple of months ago.
A friend of the couple tells HELLO!: "Peter and Lindsay made the difficult decision to separate as they were spending less time together with work and family commitments.
"Peter's business commitments and work in F1 meant he has been away and travelling non stop.
"It obviously came as a shock as most people thought they were absolutely rock solid, it’s very sad. Peter has been travelling all over the world and has been incredibly busy and Lindsay is based up in Scotland, so it's been hard for them to see each other."
Peter's official spokesman declined to comment, saying it was a "private matter".
The Princess Royal's son is understood to have spent time with Savannah, 13, and Isla, 12, the daughters he shares with ex-wife Autumn Kelly over Easter.
His roles as head of partner acquisition for the rights agency CSM Sport & Entertainment and as an ambassador for ISPS Handa have seen him travelling all over the world in recent months. He was in Bahrain for the F1 Grand Prix in March and in Australia the same month.
Peter and Lindsay got together in 2020 after he separated from Autumn in 2019 and made their official debut as a couple at the Epsom Derby in June 2022.
Lindsay, who has two children of her own, was described as "a breath of fresh air" by a friend of the couple and Peter introduced her to his grandmother Queen Elizabeth II following a shooting party at Windsor in 2022.
They went on to appear together at a string of high-profile royal family events, including the Platinum Jubilee celebrations, Royal Ascot, Wimbledon and the Coronation Concert in May 2023.
At the time, a friend told HELLO! that "it meant a lot" to Peter to be able to bring Lindsay to the Concert, adding: "He is in a great place at the moment and could not be happier in either his private or personal life."
Lindsay was a classmate of Peter's sister Zara while at Gordonstoun and attended her wedding to Mike Tindall in 2011 as well as the joint christening of the Tindall’s son Lucas and Princess Eugenie and Jack Brooksbank’s son August in 2021.