Japan has finalized an agreement with the United Kingdom and Italy to jointly develop a next-generation fighter aircraft by 2035, a move that will see Tokyo cooperate for the first time with countries other than the United States to meet a major defense requirement.

The move involves merging the Japanese Defense Ministry’s F-X fighter plans with those for Britain’s Tempest. Those programs were to replace the Air Self-Defense Force’s F-2 jet and the Royal Air Force’s Eurofighter Typhoon, respectively, with both aircraft being developed to a similar schedule and needing to meet almost identical requirements.

The stealthy, twin-engined fighter will be developed under the Global Combat Air Programme, with Japan’s Mitsubishi Heavy Industries and Britain’s BAE Systems set to lead the project.