SriLankan Airlines has firmed its tentative order for four Airbus A350-900s, a deal which had been disclosed at the Paris air show.
The order is part of a deal covering 13 aircraft.
SriLankan had already ordered six A330-300s on 19 June. Airbus says it has since firmed an agreement for four A350s - bringing to 35 the number of customers for the twinjet type.
The A330s and A350s will be fitted with Rolls-Royce engines.
SriLankan is also taking three additional A350-900s on lease. The combined twinjet deal will help replace the carrier's A340 fleet.