The next-generation Fiat 500 is set to be longer and wider than the current model as success in the US shapes the new car's design.
The US became the Fiat 500′s largest market last year, with 43,772 sales in the States outgunning the pint-sized Italian's 42,919 units in its home market.
Fiat insiders told industry journal Automotive News this popularity means the designers of the all-new model are paying special attention to the wants and needs of US customers in the development phase.
The second generation of the born-again city car will evolve rather than revolutionise the styling of the current model when it launches in 2015, continuing to pay tribute to the iconic original that debuted in 1957.
Convertible 500C and sporty Abarth variants will follow roughly 12 and 24 months later after the standard three-door hatchback.
Automotive News also reports Fiat is working on a Fiesta-sized hatch to sit between the 500 and the high-roofed Fiat 500L?(pictured). The as-yet unnamed model is set to replace the ageing Punto by 2016.
Ahead of the second-generation hatch-based models will come the Fiat 500X, which is believed to be about 150mm longer than the 500L and will be available with four-wheel drive.
The 500X will enter production in the second half of next year in the US and Italy alongside its sister car, the new 'baby Jeep'.
Australian Fiat 500 sales are up more than 250 per cent so far this year after the factory assumed responsibility for local distribution and overhauled the range, significantly introducing a new $14,000-driveaway entry-level model.
