Fincantieri will build a further four ships for Viking, in a deal worth around €1.7bn.
As part of an agreement signed in March 2018 for six vessels, Fincantieri and Viking have now actioned the contracts for the construction of the third and fourth ships.
The companies also announced the signing of a contract for the fifth and sixth vessels to be built subject to access to finances.
Fincantieri plans to deliver the third and fourth ships in 2026 and 2027, respectively, with the other two units planned for delivery in 2028.