However, the three cars will all be different sizes: industry journal Automotive News Europe the French brand's Twingo will be the biggest at 3581 millimetres long, while the second-generation Smart ForFour will be 3505mm long, and the third-generation Smart ForTwo will be just 2692mm - almost exactly the same size as the current car.
Smart CEO Annette Winkler said the three cars will share internal combustion engines but the Smart duo will feature the brand’s traditional B-pillar design and have no resemblance to the rear-wheel-drive French city car.
In another point of differentiation, Smart will also offer buyers an electric vehicle version of its tiny models. The Twingo and new Smart models will also have the option of a 51kW 1.0-litre or a 66kW turbocharged 0.9-litre three-cylinder petrol engine.
The new Smart cars are tipped to break cover at September's Paris motor show and debut in European showrooms by the end of the year.
Winkler also confirmed that while the ForTwo – spied late last year – will reach the US in August 2015, the ForFour won't join it in that market as sales expectations are not high enough to validate homologation costs.
The second-generation Smart ForTwo is still on sale in Australia and is currently in runout at $18,990 driveaway for the Coupe and $20,990 driveaway for the Cabrio. It's expected the new version will be offered with hard- and soft-tops, too.
The Renault Twingo remains unlikely to reach Australian showrooms at this stage.