The hairstyle was unmistakable - surely that was Becks with wife Posh? But just what were Britain's most famous celebrity couple doing in Southampton docks yesterday?

Then there was someone looking suspiciously like Sir Alex Ferguson, Ab Fab's Eddy and Patsy, Peggy from the Queen Vic, Joan Collins was there with Ali G and even Basil Fawlty made an appearance.

They were in fact all lookalike doubles who were in the port to help celebrate the arrival of the city's own identical twins, the cruise ships, Adonia and Oceana, already dubbed Southampton's White Sisters.

Today the Queen's granddaughter, Zara Phillips, becomes the godmother of Adonia and her mother, the Princess Royal, takes on the same role for Oceana when they officially name the vessels in a dockside ceremony.

In a unique royal event, Zara and the Princess Royal will make history in performing the first double event of its kind seen in the UK when they name the two P&O Cruises' superliners.

The dockside ceremony, that culminates in a firework display, will be watched by hundreds of specially invited guests from all over the world.

After being met by the masters of the two identical, 77,499 ton ships, Captain Steve Burgoine from Oceana and Captain Rory Smith, from Adonia, the royal party will board the vessels to meet the crews and tour the decks.

After a series of champagne receptions and a gala dinner, Zara and the Princess Royal are due to return, at about 9.30pm. to the dockside where the ships will be bow-to-bow at 102 and 103 berths in the Western Docks.

Military bands, including the Royal Marines, and the Southampton University Gospel Choir, will be performing as well as a colourful light show projected on to the sides of Oceana and Adonia.

The namings take place in alphabetical order and the highpoint will be when two bottles of champagne are simultaneously sent crashing against their hulls.

It is the first such engagement for Zara, tenth in line to the throne, but is the second time that the Princess Royal has named a P&O Cruises ship in the docks. In April, 2000 the Princess named the 76,152 ton Aurora.

On Saturday both ships are expected will make a dramatic sight as they leave together at about 5pm for cruises.

FOR MORE INFORMATION ON THE 'WHITE SITERS' GO TO OUR DEDICATED shipping SITE THIS IS SHIPPING AT: www.thisisshipping.co.uk