Photo tour: Royal ship christenings through the years

Another year, another royal christening.

When Britain's Queen Elizabeth II officially names P&O Cruises' new Britannia on Tuesday in Southampton, England, she'll be continuing a long tradition of royals christening passenger and cruise ships.

As can be seen in our new photo tour of royal christenings, in the carousel above, the event comes just two years after the Queen's granddaughter-in-law, Duchess Kate, christened Princess Cruises' new Royal Princess.

Duchess Kate, in turn, was following in the footsteps of her late mother-in-law, Princess Diana, who christened the original Royal Princess in 1984. And Queen Elizabeth II herself is no stranger to royal christenings, having named P&O Cruises' Oriana as well as four Cunard ships over the years. Even the Queen's daughter-in-law, Camilla, Duchess of Cornwall, has christened a cruise ship.

In addition to P&O Cruises, Princess and Cunard, passenger lines that have seen royals christen ships over the past century include Holland America, which has a long association with Dutch royals, and Royal Caribbean. In the latter case, royals both real and imagined have played a christening role: Queen Sonja of Norway christened Royal Caribbean's Majesty of the Seas in 1992, while fictional Princess Fiona from DreamWorks' Shrek films christened the line's Allure of the Seas in 2010.

At 141,000 tons, Britannia is the biggest cruise ship ever designed specifically for the British market. It'll hold 3,647 passengers at double occupancy.

For more photos from the christening of the Royal Princess with Duchess Kate, click through the carousel below.