TURIN – A new Alfa Romeo Spider will be built by Mazda in Japan – and make its way to the U.S. as part of the brand’s market return, under a preliminary deal between Mazda and Fiat announced today.

The plan, which drives another nail in the coffin of the fading partnership between Ford and Mazda, calls for the Italian and Japanese auto makers to cooperate on a new rear-drive platform that will be used to produce the Spider and the next-gen Mazda MX-5 Miata 2-seat roadsters.

The cars will be built at Mazda’s plant in Hiroshima beginning in 2015. The roadsters will be distinctly styled and the Alfa will have its own “made in Italy” engine.

There’s irony in the deal that will see Mazda play a key role reinventing the Spider. Many buyers see the iconic MX-5 Miata as the successful heir to the Alfa Romeo Giulietta and Spiders that dominated the class in the ’60s and ’70s. But the partnership will improve the economies of scale for both auto makers in producing the low-volume sports cars.

Fiat CEO Sergio Marchionne calls the memorandum of understanding an agreement that “clearly demonstrates our commitment to Alfa Romeo and the determination to grow it into a truly global brand.”

The move also may give Fiat the tools to begin firming up a third leg to its global-strategy stool that has a base in Europe with Fiat and in North America through Chrysler, but lacks a solid partner in the Asia/Pacific region.

It also could be a key step in Mazda’s future survival. The Japanese auto maker has been trolling for a strategic partner ever since Ford began its slow exit from a product-development partnership and equity relationship in the past couple of years.

“Establishing technology and product-development alliances is one of Mazda’s corporate objectives, and this announcement with Fiat is an important first step in that direction,” says Mazda President and CEO Takashi Yamanouchi.

The pact is expected to be finalized in second-half 2012, and the auto makers say they will discuss further cooperative deals as well.