Passengers travelling on British trains during the weekend of King Charles' coronation will hear a special message recorded by the monarch himself, including a reminder to "mind the gap," officials said on Friday.
The announcement, by Charles and his wife Camilla, will be heard by anyone travelling by train or the London underground "tube" network between Friday and Monday.
The coronation takes place on Saturday.
"My wife and I wish you and your families a wonderful coronation weekend," passengers will hear Charles say, followed by wishes for a happy journey from Camilla: "Wherever you are travelling, we hope you have a safe and pleasant journey."
"And remember, please mind the gap," Charles will add.
The phrase - intended to warn passengers about the gap between train carriage and platform - will be instantly familiar to the British and visitors to the country.
"The coronation is a rare and exciting event and we very much look forward to welcoming passengers with this special message," said Jacqueline Starr, chief executive of the Rail Delivery Group, which represents Britain's rail industry.
The recording will be played in all 2,570 railway stations across the UK, the group said.