Mars is Viking’s seventh ocean ship, and will join its sisters in service shortly sailing the Mediterranean, Scandinavia and northern Europe before repositioning to Australia and New Zealand later this year.

The low-key event was held at Valletta’s grand harbour on Tuesday (17 May), coinciding with Norwegian Constitution Day, with Lady Carnarvon offering her blessing via video link from Highclere Castle, home of Downton Abbey. It also featured a performance by Norwegian singer Sissel Kyrkjebo, godmother of Viking Jupiter.

Viking said Valletta was a particularly significant location for the line after Malta became one of the first countries to welcome the line’s ships when it restarted operations in 2021.

To mark the naming and line’s 25th anniversary "in a private and more meaningful way", Viking and Lady Fiona Carnarvon have each donated £10,000 to 25 charities supporting a range of causes "important to both Viking and the Carnarvon family".

Mars was built at Fincantieri’s shipyard in Ancona and was delivered to Viking last week, becoming the newest of seven sister ocean-going ships; it has 465 all veranda staterooms accommodating 930 guests.

Lady Carnarvon has welcomed viewers of Viking TV to Highclere in the past as part of her ongoing series, At Home at Highclere, leading more than 20 virtual tours over the past two years. She is also godmother to Viking Scadi, one of the line’s longships.

"Many of our guests were introduced to both Viking and Highclere Castle while watching Downton Abbey, and over the years we have continued a close friendship with the Carnarvon family as they have welcomed our guests into their home. We are very grateful that Lady Carnarvon has honoured us by serving as godmother of our newest ocean ship," said Viking chair Torstein Hagen.

Lady Carnarvon added: “I am honoured and privileged to be the godmother of the Viking Mars. I have no doubt she will delight the many guests who travel with her around the world. For more than a decade, Viking and Highclere have been linked through both Downton Abbey and life, and we look forward to continuing welcoming the extended Viking family to explore our home for years to come."