Royal Caribbean Cruises subsidiary Celebrity Cruises has signed a preliminary deal with the French arm of Korean shipbuilding giant STX for two new vessels valued at 1.2 billion euros ($1.5 billion).
The 1,450-cabin ships are due for delivery in 2018 and 2020, the president of STX France, Laurent Castaing, said, announcing the signing of the letter of intent on Thursday.
The deal will come as a major boost for the Saint-Nazaire yard in western France, which has struggled to secure new orders in recent years.
The shipyard is also facing uncertainty over the French government's decision to suspend delivery to Russia of a warship being built in Saint-Nazaire in a row over the Ukraine crisis.
The new 300-metre (nearly 1,000-foot) cruise liners will be able to carry 2,900 passengers and could be put into service anywhere around the world, Castaing said.
STX is already engaged in building two giant cruise ships for Royal Caribbean.
The Oasis-class ships, the largest of their type in the world, are capable of carrying 8,000 passengers and crew.
The order marked a turnaround for the yards at a time of falling orders and rising unemployment.