Global demand for the Fiat 500 has been so high that its sales have been backlogged for months, and now the company is reportedly adding a hybrid powertrain to the modern classic to make it even more attractive. Based around an upcoming efficient two-cylinder petrol engine and a bespoke battery pack, the new 500 hybrid promises emissions below 90g/km of CO2, which should translate into roughly 80mpg (2.94L/100km) fuel efficiency.

In addition to adding value and environmental credibility to the small hatch, the move could also prepare the company for the EU's strict 120g/km C02 emissions averages, due to begin enforcement in 2012. The report of the hybrid car's development, originating with Auto Express, also indicates that the two-cylinder 900cc engine that will power the hybrid will make its debut at the Goodwood Festival of Speed next summer. A stop-start ignition system and dual-clutch gearbox are also rumored to be on the inclusion list, further improving fuel efficiency.

The Panda Aria concept shown at last year's Frankfurt Motor Show contained a 900cc twin-cylinder engine, and since the 500 is based on the same platform as its Panda cousin, it's reasonable to expect the same engine to slot into the 500. Aside from the obvious displacement difference, the two-pot is also 20% lighter than a four-cylinder motor, but is still capable of providing 65hp (48kW) in naturally aspirated form and 105hp (78kW) when a turbocharger is added.

The cars are expected to hit showroom floors sometime in 2011, but may make their motor-show debut late this year.