Mercedes' revolution of their nomenclature will see the introduction of the CLA to the line-up and our spies have caught a development prototype while it was out testing recently.

Spy photographers have caught a development prototype of the new CLA-Class while it was out testing recently.

As Mercedes' revolution of its nomenclature gets under way, all coupes produced by the German auto maker will adopt the CL prefix. Because the model seen here is based on the A-Class, it will take the CLA label. The same strategy has been adopted by the CLS four-door coupe which is based on the S-Class while the next coupe version of the C-Class will be the CLC.

The CLA will naturally inherit the engine line-up from its A-Class sibling that will be flagshipped by an AMG version. Reports have stated the AMG version could get as much as 335 bhp (250 kW / 340 PS) from its turbocharged 2.0-liter unit. This would put it squarely in the realm of the BMW 1-Series M Coupe that possesses an identical output.

Styling continues to be well hidden on the prototype caught here but we expect a similar front end to the A-Class, possibly with just a single horizontal chrome bar behind the Mercedes star.

The new Mercedes CLA will be launched during 2013 as a 2014 model following a world debut that will be performed later this year.