US carmaker Ford has turned to Japanese rival Toyota for help with building environmentally friendly cars.
The US firm is licensing the technology behind Toyota's Prius hybrid vehicle, which switches between petrol and electricity to cut down on emissions.
Neither side would spell out how much money is involved in the deal.
But Toyota's system will now contribute to the hybrid system Ford is developing for a cleaner sports utility vehicle due to go on sale later this year.
The Prius has been on sale since 1997, but demand has only begun to pick up rapidly in the past year.
The car has won a range of industry awards, and has now sold more than 200,000 units worldwide.
Toyota's Japanese rival Honda also has hybrids on sale, and Nissan has an existing deal - broader than Ford's - to license Toyota's technology.
But Ford is the only US carmaker to be ready to enter the market.
The company originally hoped to have its Escape SUV ready to go last year.
The Escape is now likely to face competition from Toyota itself, which is planning both a luxury SUV and possibly a pickup truck.
Ford lost its spot as the world's second biggest car seller to Toyota last year.