Carnival Cruise Line will grow and update its fleet in 2019 via a ship swap with sister brand P&O Cruises Australia.

Carnival will add a sister ship to the Carnival Vista, a vessel that was originally designated for Carnival Corp.’s P&O Cruises Australia brand. The Carnival Splendor, which was delivered in 2008, will be transferred in 2019 to P&O Cruises Australia in conjunction with the change.

The new ship, as yet unnamed, will be the third in the class, which was launched last year with the debut of the Carnival Vista. The second in the class, the Carnival Horizon, is also to sail for Carnival Cruise Line and is scheduled for delivery in 2018.

The 133,500 ton Vista ships carry 3,954 passengers at double occupancy and are 18% bigger than the Carnival Splendor, which carries 3,006 passengers.

In a statement, Carnival president Christine Duffy said the addition of additional Vista-class ships would enable Carnival to offer the Vista-class experience from different homeports and create new itinerary options.

Specific itinerary, homeport and ship details for the third vessel have yet to be announced.

The Vista “has proven to be the most innovative and popular ship we’ve ever introduced,” Duffy said.