British Airways will add the Boeing 777X to its fleet, with as many as 42 of the next-generation jets taking wing between 2022 and 2025.
BA has opted for the Boeing 777-9 version, which will be decked out with 325 seats across four cabins – a mix that's expected to see the new Club World Suites business class which will debut mid-year on its Airbus A350s, and potentially an all-new first class cabin.
The arrival of the 777-9's will mark the end for 14 Boeing 747-400 jumbo jets plus four Boeing 777-200s.
BA parent company IAG says that 18 Boeing 777-9 aircraft can be counted as firm orders, with options for 24 more.
"The new Boeing 777-9 is the world's most fuel efficient long-haul aircraft and will bring many benefits to British Airways' fleet," said IAG chief executive Willie Walsh.
"It's the ideal replacement for the Boeing 747 and its size and range will be an excellent fit for the airline's existing network."
British Airways' vote of confidence in the Boeing 777X comes ahead of the aircraft's official rollout on March 13, with first delivery to launch customer Lufthansa in 2020.
Lufthansa will use its Boeing 777-9 fleet to launch its own all-new business class seat (below).
BA joins a growing roster of airlines signing up for the Boeing 777X – alongside Lufthansa sit Cathay Pacific, Singapore Airlines, Emirates, Etihad Airways, Qatar Airways and Japan's ANA.
Also in the frame are Qantas and Air New Zealand, both of which are casting around for long-range jets capable of making non-stop flights from the 'down under' corner of the globe to the likes of New York and London.
Boeing has pitched the 777-8 to Qantas for the airline's ambitious Project Sunrise, with an ultra-long range version of the Airbus A350-1000 also in the ring. Qantas will make its decision and place an order for the globe-striding Project Sunrise fleet later this year.
The 777x jets combine the form of the popular Boeing 777-300ER with the advanced design, technology and passenger-friendly traits of the Boeing 787 Dreamliner such as larger windows, a lower effective cabin altitude, increased humidity levels and cleaner air – the last three of which are crucial in minimising the effects of jetlag.