British designer Mark Adams, the man behind the Vauxhall Astra GTC set to be launched later this year, says the soft top will help to save weight and improve the drive of the new drop-top.
It will replace the current three-piece folding metal roof and Vauxhall says it will be cheaper to produce and provide insulation against wind and other external noise.
The model was first announced in 2009 and the first look at the new cabriolet has finally been revealed in a sketch released by the car maker this week.
Based on the Astra GTC coupe, the Cabriolet will be a four-seat model to replace the current Astra Twintop.
Its origins in the sporty Astra GTC coupe mean engine choices are expected to include one or more of the three units offered with the three-door model.
These include a 1.4-litre petrol and a range-topping 180bhp, 1.6-litre engine. A diesel version has not been confirmed by Vauxhall, but the 2.0-litre diesel used in the GTC is the most likely option if one does arrive.
The new Vauxhall Astra Cabriolet will go on sale in the UK in 2013 once production begins in the Gliwice plant in Poland.
When it does arrive, it will be the latest in a range of new Vauxhall cars, including the Vauxhall Ampera extended range electric vehicle in 2012 and a small city car to replace the Agila in 2013.
It will join the Vauxhall Astra range which consists of the hatchback version in three- and five-door variants, a Sport Tourer model and the forthcoming Vauxhall Astra GTC.
Prices for the cabriolet have yet to be confirmed, but a starting price in the region of £20,000 is expected.