The lyrics to the national anthem will change from “Queen” to “King” and “her victorious” to “him victorious” to mark that King Charles III has now taken over as monarch.
It comes after crowds spontaneously sang the version of the song outside of Buckingham Palace on Friday as the King arrived with the Queen.
The anthem is also expected to be sung at the Kia Oval on Saturday as the England v South Africa Third Test Match resumes. It was paused on Friday following the Queen’s death.
Members of the royal family are not expected to attend the 6pm service at St Paul’s, which is open to the public and is being broadcast live by the BBC.
Audio of the King’s televised address to the nation will be played inside the cathedral if it coincides with the service.
A total of 2,000 seats have been allocated to the public on a first-come-first-served basis, with all of the wristbands for the evening service being distributed within three hours, a cathedral spokeswoman said.
A spokeswoman for the cathedral said Prime Minister Liz Truss, who will deliver a reading at the service, is expected to be joined by Lord Mayor Vincent Keaveny.