Wales has been chosen by GE Aviation to provide maintenance and repair for the world's largest and most fuel efficient jet engine, the GE9X.
The company is investing £15m and the Welsh Government £5m.
The work will take place at GE Aviation's Nantgarw site which already employs 1,400 people, with extra jobs likely to come.
The announcement follows First Minister Carwyn Jones' meeting with US company executives in Washington DC.
The funding will be used to equip the Nantgarw facility and improve the skills of the workforce over the next five years to ensure it is ready to maintain the GE9X fleet when it begins service with Boeing.
"This is a great day for Wales and particularly for our communities across the Valleys", said GE Aviation Wales managing director La-Chun Lindsay.
"More than 85% of our employees are from the surrounding area and are thus firmly rooted in our local community.
"I'm so pleased that securing the GE9X means that future generations will have the chance to fulfil their dreams of working at GE Aviation Wales and will have the same fantastic opportunities that have existed throughout the site's proud history."
Carwyn Jones said: "I am delighted Welsh Government is supporting this very significant investment in one of our flagship operations.
"GE Aviation Wales is one of the largest aircraft engine maintenance facilities in the world and today's announcement ensures it will maintain its position as the global centre of excellence for wide bodied jet engines that will now also include GE's latest engine, the GE9X."
The news was also welcomed by Welsh Secretary Alun Cairns, who said the investment underlined Wales' reputation as a leader in aviation technology, adding: "Once again, the skill of the Welsh workforce has proven a world beater."