Dame Kelly hits the button to release the champagne bottle

A dockside auditorium was specially built for Tuesday evening's ceremony, which saw fireworks light up the decks of the �200m, 85,000-tonne ship.

Arcadia, P&O's latest liner, can carry more than 2,000 passengers and is the length of 30 double-decker buses.

It will be the first Southampton-based ship to offer weddings at sea.

Dame Kelly named the ship by smashing a champagne bottle into its side, as thousands of people watched the ceremony on a big screen in the city's Mayflower Park.

Dame Kelly said: "This is an amazing moment. I am thrilled to have been asked by P&O Cruises to be godmother of the beautiful Arcadia."

Arcadia is revealed as a curtain and dancers lift to the ceiling

She added: "This is how gold medals should be awarded in the future."

The Italian-built ship, which arrived in Southampton last week, has a top speed of 22 knots and includes two swimming pools, a three-tier theatre and a casino.

On board, passengers will also be able to chose food from menus created by celebrity TV chef Gary Rhodes.

In the summer months, Arcadia will cruise around the Mediterranean, while in the winter she will be berthed in Barbados, taking her passengers around the Caribbean.

Her launch brings the number of cruise ships working out of Southampton to 10.