Three British liners known as Cunard's 'Queens' were to meet in an historic first in their home port of Southampton on Tuesday, the company said.
The 148,000-tonne Queen Mary 2, the biggest cruise ship in the world when it was built, and Cunard's newest 'Queen', Queen Victoria, will salute the venerable QE2 on the day she celebrates the 39th anniversary of her official entry into service.
Thousands of people are expected to line Southampton's docks in southeast England to see the three ships as they sound their whistles together shortly after 1600 GMT before Queen Mary 2 embarks on her first transatlantic crossing of the year.
The 17-storey Queen Mary 2 entered service in January 2004 with a maiden voyage from Southampton to Florida.
Its construction was marked by tragedy when a walkway collapsed in the French port of Saint Nazaire, killing 16 people.
It was overtaken in 2006 as the world's largest cruise ship in terms of volume by the Finnish-built Freedom of the Seas, which can carry up to 4,400 passengers to the Queen Mary's 2,620.
The QE2 went into service in April 1969. She is to undergo a refit later this year.