Spotted (completely by chance) by the head of our spy photography agency, he only managed to snag some photos of the new high-performance sedan from the rear.
We can see the car's puffed up front and rear wheel arches, although the units at the front look to be a temporary hack job. Naturally, the new M3 rides on wide, low-profile rubber at both ends.
Four exhaust tips poke out from underneath the car's rear bumper, and there's a subtle lip spoiler on the trailing edge of the boot lid.
With camouflage on every body panel except the roof, not to mention a number of false panels and temporary components, it's impossible to see the smaller details that will visually separate the M3 from its more prosaic siblings.
This vehicle uses the same wing mirrors as the 3 Series sedan prototype spied back in August. We'd wager considerable amounts of money on more heavily-styled M-specific units to be used on the final production vehicle.
Rumours indicate the next-generation M3 might stick with the same basic powertrain as today's car, meaning an updated version of the 3.0-litre twin-turbo straight-six petrol engine.
It's not known when the new M3 will make its debut, but a 2019 launch would be our guesstimate.