The front bumpers of both cars remain obscured, suggesting that we can expect a new look at the front end. There's also light camouflage along the rear bumper, heavier in the case of the AMG model, pointing to smaller changes at the rear.
It's expected that visual changes for the updated S-Class will be limited to new front and rear bumpers, grille, headlight and tail-light graphics, and, possibly, other garnish changes, such as alloy wheels.
Now that the smaller C-Class and E-Class models have been completely redesigned and feature styling that deviates little from the S-Class's template, this update may provide a little bit more visual space between the various models in the company's rear-wheel drive sedan family.
While our friends were unable to capture an interior view, all the prototypes seen so far have had extensive amounts of camouflage on the inside.
This indicates that Mercedes-Benz may be upgrading the S-Class' Comand infotainment system to take it one step beyond the recently introduced E-Class.
Possible changes include larger or rearranged screens for the dashboard and instrument panel, revised controls in the centre stack, gesture sensing mechanisms, and more driving aids.
A power bump could also be on the cards for the S63 - possibly even to the extent of dropping its 5.5-litre turbo V8 in favour of the new 4.0-litre unit making its way across the AMG line-up.
That engine is expected to deliver upwards of 445kW in the upcoming new-generation AMG E63 S, which could mean even bigger numbers for the S63.
Given that the current-generation S-Class made its debut in 2013, its replacement is likely due around 2019, meaning that the facelift glimpsed here could debut later this year or very early in 2017.