Mazda and Alfa Romeo have finalised the terms of the agreement that will see them collaborate on a pair of open-top two-seat sports cars to be built at the Japanese brand's Hiroshima plant from 2015.

Alfa-Romeo-4C-Concept

Alfa Romeo's roadster – rumoured to be a convertible 'Spyder' version of the Alfa Romeo 4C coupe (above) that is due to launch later this year – will be based on the all-new fourth-generation Mazda MX-5.

Unlike the partnership that saw the creation of the Subaru BRZ and Toyota 86 twins, the Mazda/Alfa agreement stipulates that both rear-wheel-drive sports cars will be differentiated with distinctive, brand-specific styling and feature proprietary engines unique to each model.

Mazda says it hopes to revitalise global enthusiasm for convertible two-seaters through the partnership as well as enhance its development and production efficiency.

For Alfa Romeo, the agreement presents the opportunity to deliver a modern interpretation of a classic roadster as the brand works towards the launch of nine new or updated models by 2016.

Unlike the Alfa Romeo 4C coupe, which is yet to be officially confirmed for right-hand-drive production, the roadster’s MX-5 origins guarantee that it will be available to RHD markets like Australia and the UK.