Prince Charles reportedly snapped at Princess Anne while at this week’s garden party at the Palace of Holyrood House in Scotland. A photo of the siblings in an alleged argument has been released.

In the snap, the future king has a stern look on his face while looking at his younger sister’s direction. Initially, Princess Anne was walking close to her brother, but after the heated exchange took place, she stayed a few steps away from him.

An onlooker said that it appeared as though Prince Charles made a go at Princess Anne because something got his goat. However, a source for the palace has not confirmed or denied the recent claims.

Growing up, Prince Charles and Princess Anne have always had a complicated relationship with each other, which only got worse because of their dad, Prince Philip. The Duke of Edinburgh preferred Princess Anne over Prince Charles because she was more like him.

Gyles Brandreth, a royal biographer, said that Prince Philip saw Prince Charles as a romantic person, while the Duke of Edinburgh is a pragmatist. For this reason, the two royal men didn’t really get along well.

Vickie Arbiter, a royal correspondent, also said that Prince Philip preferred Princess Anne over Prince Charles because she appeared to be stronger than her older brother. And when they were much older, Prince Charles and Princess Anne had a heated family confrontation.

After the story of Prince Charles’ affair with Camilla Parker Bowles was made public in the press, reports also swirled that Princess Anne also had an affair with Camilla’s ex-husband, Andrew Parker Bowles. During their argument, Princess Anne berated Prince Charles for his adulterous behavior, and Prince Charles reminded her that she had her own situation to worry about.

But when the royal siblings are in public, it appears as though they get along just fine. They have attended multiple engagements on behalf of Queen Elizabeth II and would continue to do so for years.

Prince Charles Britain's Prince Charles kisses Lady Sarah McCorquiodale, while her sister Lady Jane Fellowes looks on at RAF Northolt Airport near London, 31 AUG, following the arrival of Charles and the casket containing the body of his former wife, Diana. MARTIN HAYHOW/AFP/Getty Images