"May God bless her and all who sail in her," Kate, the ship's godmother, said right before the four-gallon Nebuchadnezzar (equivalent to 20 bottles) crashed against the ship's hull.
Wearing a $260 Dalmatian-print coat from high street store Hobbs and a bespoke hat by Sylvia Fletcher at Lock & Co., Kate arrived around 11:35 in the morning to take her place on the quayside stage under the shadow of the 141,000-ton, 217-ft.-tall ship in Southampton.
Smiling at what was her penultimate public engagement before she takes maternity leave, Kate stood to attention and was sometimes distracted by her long hair blowing in the blustery harbor wind.
Princess Cruises CEO Alan Buckelew told the crowd, "We can think of no more fitting godmother for our magnificent new ship. Her Royal Highness is an inspiring ambassador for Britain, and she is admired around the world for her style and grace, and for her compassion for others."
Helping Kate at the ceremony, besides ship captain Tony Draper, were two youngsters from one of her charities, East Anglia's Children's Hospices. Izzie and Charlie Rowbotham, who presented Kate with the scissors to cut the rope, lost their brother George when he was 21 months.
After the ceremony, Izzie, 15, told PEOPLE, "She was really lovely. She wanted to know how [the East Anglia's Children's Hospices] had helped us, so we told of their care and support for us all in the family."
Their mother Alie, from Milton, near Cambridge, added, "We were so proud to be involved. She looked amazing and seemed really excited when the Champagne bottle exploded."