King Charles has hosted the first film premiere at a royal palace - a documentary chronicling his lifetime work of championing nature was shown at his historic Windsor Castle home. King Charles and Queen Camilla hosted the premiere at Windsor Castle. I've said that for the last 40 years but anyway, there we are," Charles ruefully says on the battle to save the planet. "It would be nice to try and see if we can get through to people, but who knows?" Charles said.