Frankfurt Auto ShowMercedes-Benz has a hybrid surprise up its sleeve for September’s Frankfurt auto show.

“I can confirm we will show something concerning hybrid technology,” a Mercedes spokeswoman tells Ward’s. The auto maker reportedly plans to reveal a hybrid diesel version of its large S-Class sedan and a CLK roadster with integrated starter-generator technology.

The spokeswoman says it is too early to confirm diesel technology is part of the hybrid setup and she declines to say whether the S-Class, which is redesigned for the next model year, or CLK are the platforms for the Frankfurt announcement.

If a hybrid S-Class is in the offing, it likely will be an evolution of what bowed in 2004 at the Detroit auto show. That concept carried a V-6 gasoline engine and a pair of electric motors and was capable of 309 hp and 30 mpg (8L/100 km), Mercedes says.(See related story: Mercedes Previews World’s First Rear-Drive Hybrid)

Diesel is a likely option for DaimlerChrysler AG’s luxury brand, given its commitment to the fuel in Europe and its pushing new technology to the U.S. market in its E-Class lineup.