Cadillac XTS spy shot

Work is well underway on Cadillac's upcoming new flagship. The XTS is slated to replace both the STS and DTS, and while this isn't the first time we've seen a test mule out in the open, it could be our best glimpse yet.

The new sedan is said to be riding on an extended version of General Motors' Epsilon II platform – the same architecture that underpins the Buick Regal and LaCrosse, the next Chevrolet Malibu and the new Saab 9-5. Power is expected to come in naturally-aspirated and turbocharged V6 forms, driving either the front wheels or all four depending on specification, when it comes along likely sometime late next year as a 2013 model. A turbocharged four has also been rumored, and of course we'd love to see a high-output XTS-V.

Our intrepid paparazzi say the XTS prototypes are wearing very similar camouflage to the much smaller ATS – which was beefed up to disguise its form under development. Very clever, GM, but not clever enough. Take a look at the spy shots in our gallery for a closer look.