Expected to do 31 miles in electric mode.

It does not come as a big surprise that Mercedes is prepping a plug-in hybrid derivative of the next-generation A-Class when you take into account the official images showing the interior did spill the beans about the electrified setup. Caught by the spy camera freezing in a car park somewhere in northern Sweden, the plug-in hybrid prototype had an extra fuel cap as well as 'high voltage' and 'hybrid' stickers denoting its eco-friendly powertrain.

Update:

While hybrids such as the C350e, E350e, and the new S560e have the cap for the charging port mounted within the rear bumper under the rear tail light, on the A-Class it’s positioned on the rear bumper on the right side. Those official images with the A-Class's cabin hinted the plug-in hybrid version will have an all-electric range of approximately 31 miles, but it's better to wait for an official number from Mercedes.

What’s particularly interesting about this prototype is the absence of a visible exhaust system. The rear section of the underbody appears to be fully concealed and although our spies did attempt to track down the exhaust and photograph it, their efforts were futile. One logical explanation might reside in the fact that this was an early prototype and might have had a provisional setup with a shorter exhaust. One could speculate this was fully electric, but the yellow 'hybrid' sticker on the windscreen says otherwise. 

Our first contact with the next-generation A-Class will be next month at CES in Las Vegas where Mercedes will introduce a new infotainment system for compact cars. The 'Mercedes-Benz User Experience' (MBUX), as the system is known, will boast a 10.25-inch touchscreen in its highest specification and will be paired with a fully digital instrument cluster of the same size on the more expensive trims.

Also check out:

A full reveal of the new A-Class is expected to take place a couple of months later, specifically at the Geneva motor show in March. The saloon will arrive shortly afterwards. Further down the line, the CLA and CLA Shooting Brake will also be updated, as well as the B-Class MPV and the GLA SUV.

Gallery: Mercedes A-Class plug-in hybrid spy photos