The camouflaged machine appears to be GM's new Cadillac GT3 car.
A number of photos, including the one above, have been floating around on Twitter. The images leaked appear to show the camouflaged Cadillac GT3-spec machine that GM may be planning to field in the Pirelli World Challenge.
The car certainly looks like the GT3 version of the 2015 ATS-V, which is set to replace the Cadillac CTSV-R. The current car is dominating the PWC and is en route to a third consecutive championship this year.
GM has yet to officially reveal their 2015 plans for the series.