Sales of the SL, one Mercedes' most iconic models, have dwindled in its current generation, and company sources had not seen evidence of a replacement model in the product plan.
However, speaking to Autocar at the Geneva motor show, Zetsche confirmed that Mercedes was working on a replacement for the SL, although he did not put a date on its launch.
"We are working on a next generation of the SL," Zetsche said. "The plan is to make a real wow car, a stunning car."
Zetsche said such a bold step was needed for the SL, as the model always performed best when it was not as conservative as the current model is.
"Whenever we accomplished that in the past, the SL has had a very good performance in the marketplace and that's where we want to go."