Fiat and Mazda have signed a final agreement to jointly produce convertible two-seater Alfa Romeo and Mazda sports cars.

The Italian and Japanese carmakers said Friday that the roadsters will go into production at Mazda's plant in Hiroshima, Japan, in 2015.

The cars will be based on the same platform — the next generation of the iconic Mazda MX-5 — but will have different styling and engines. The carmakers signed a memorandum of understanding in May.

Fiat is planning to launch nine new Alfa Romeo's by 2016 as part of its strategy to focus on higher-margin luxury cars and launch Alfa into a global brand. Most will be produced in Italy to help return European operations to profitability and revive production at underutilized plants.