London, UK - Even the memory of their beloved mother, Diana, is not enough to bring Prince Harry and Prince William back together, as the brothers preferred to keep their distance from one another at an event honoring the late princess on Thursday.

While William appeared in person at the Science Museum in London, his younger brother only joined in via video link – after the Prince of Wales had already left the event, as reported by the Daily Mail.

The Times newspaper noted that a joint appearance had not been planned, a sign of the continuing rift between the sons of King Charles.

A reporter from ITV said that it had apparently not been possible to get the two of them in the same room for the 25th anniversary of the award.

To somehow distract from the dispute, William made a special appearance at the awards ceremony.

He took to the stage to Thunderstruck by AC/DC, which is his son George's favorite song, the royal said before his speech.

In it, he paid tribute to his mother Lady Di: "She taught me that everyone has the potential to give something back, that everyone in need deserves a supporting hand in life."

The Diana Award has been honoring young people for their social commitment since 1999.