Royal Princess weighs 141,000 tons and its maiden voyage will include stops in Lisbon in Portugal, Gibraltar and Malaga in Spain.

The Duchess of Cambridge is to officially name a new cruise liner this summer.

Kate, whose baby is due in mid-July, will be at Southampton on June 13 for the naming ceremony of Princess Cruises’ 3,600-passenger Royal Princess.

The official ceremony will involve a blessing, the celebratory tradition of smashing a bottle over the hull of the ship and a performance by the Royal Marines Band and the pipers of the Irish Guards.

The duchess will also go on board for a brief tour of the new liner which will leave on its maiden voyage on June 16.

Princess Cruises’ president and chief executive Alan Buckelew said today: “It is a great honour for Princess Cruises that Her Royal Highness the Duchess of Cambridge has accepted our invitation to become the Godmother to Royal Princess.

“We are delighted that the Duchess will launch our new ship and can think of no better way to celebrate our company’s British heritage and our commitment to the country.”

Features of the new ship include a top-deck, glass-bottomed walkway extending 8.5m beyond the edge of the ship, the largest pastry shop at sea and balconies on all outside staterooms.

The Royal Princess will go on Mediterranean cruises this summer followed by Eastern Caribbean cruises beginning in the autumn.

The new ship weighs 141,000 tons and its maiden voyage will include stops in Lisbon in Portugal, Gibraltar and Malaga in Spain.