It was a rare boy’s night out. Prince Charles joined his sons Prince William and Prince Harry for an enjoyable evening but it’s all for good cause.

The royals went out in a rare joint engagement and went to the Natural History Museum in London to attend the global premiere of Netflix’s series “Our Planet.” The Prince of Wales and his sons chatted with Sir David Attenborough as they posed outside the museum.

Prince Charles expressed how proud he is of how his sons joined him to show their support to his cause. “I must say I was enormously touched to have been asked here this evening along with both of my sons to launch this really remarkable series,” the Prince of Wales remarked.

Prince Charles even revealed his sense of humor when he feigned surprise at Prince William and Prince Harry’s attendance at the event. “When they were much younger I never thought they were paying any attention to anything I was saying,” the Prince of Wales spoke about his two sons with his late wife Princess Diana. “But when I turned 70 last year, to my absolute astonishment it appeared that they had.”

The royals are often seen making public appearances in support of various causes. However, it is still rare to see Prince Charles and his two sons simultaneously attending a single event to lend their support to a specific cause. Obviously, the threat of climate change is a high priority for the three royals.

“The Prince of Wales, the Duke of Cambridge and the Duke of Sussex are continuing to use their unique positions to help highlight the threat of climate change and the multi-generational effort required to maintain our natural environment,” Clarence House said in a statement.

“Our Planet” is Netflix’s new eight-part nature-focused series that also aims to highlight the threat posed by climate change. The show is narrated by 92-year-old British naturalist David Attenborough.

Prince Charles also lauded Sir David Attenborough’s environmental efforts. “Above all he has done so much to life the veil of ignorance from our eyes about the integrated and innate beauty of our home,” the Prince of Wales said.

“We have cleared of 50 per cent of the world’s rainforests, we have destroyed 50 per cent of our coral reefs, poisoned our rivers and indeed whole swathes of the ocean with the run of industrialised agriculture. Climate change is now a very real existential threat to our whole civilisation.”

Prince Harry, Prince William and Prince Charles Prince Harry, Duke of Sussex; Prince William, Duke of Cambridge; Prince Charles, Prince of Wales; and Sir David Attenborough attend the 'Our Planet' global premiere at Natural History Museum on April 4, 2019, in London, England. John Sibley - WPA Pool/Getty Images