At the front, the headlights are more closely related to the current model as they appear to sit lower and are larger than that seen either on the CLS-Class or the A-Class. The grille comes from those newer vehicles, though. It's a very wide grille, and the lower half is wider than the upper. The same goes for the lower grilles that ape the partial dog-bone shape started by the AMG GT line. Otherwise, proportionally, the nose looks pretty similar to the A-Class.
Around the side, the profile is pulled straight from the CL-prefix cars. There's a strong arch to the window sill, and a more dramatic one for the upper part of the glass area. The same goes for the fastback C-pillar, a contrast to the more upright pillar of the A-Class.
The C-pillar descends into a tail section that is just a scaled-down version of the CLS-Class. The trunk area is more horizontal and longer than the old CLA-Class's, and it features taillights like those of the CLS-Class. The tail appears to sit higher up than that of the old CLA-Class, too. Besides preventing the slightly droopy look of the outgoing model, this design will probably improve cargo capacity.
Since this car is very close to being undisguised, we expect to see the production model soon. It will certainly be shown by the end of next year in time to be either a 2019 or 2020 model. It will probably share its mechanicals with upcoming U.S.-spec A-Class sedan.