Mercedes-Benz has published a lone teaser sketch that previews the upcoming S-Class Cabriolet. Scheduled to bow in less than a month at the Frankfurt Motor Show, the topless S will be Mercedes’ first convertible four-seater flagship since 1971.

The sketch reveals the S-Class Cabriolet will be all but identical to the S-Class Coupe from the rocker panels up to the belt line. Above that, it will get a cloth soft top that will open or close in seconds at the push of a button. The teaser shows the top in its down position, but recent spy shots reveal that the S Coupe’s sleek-looking roof line has been retained with only small modifications.

Mechanically, the Cabriolet is expected to be nearly identical to the coupe. That means it will launch with a twin-turbocharged 4.7-liter V8 engine tuned to make 449 horsepower and 516 lb-ft. of torque. An automatic transmission and Mercedes’ 4Matic all-wheel drive system will both come standard.

Mercedes-AMG will offer two performance-focused variants of the Convertible, a S63 with a 577-horsepower 5.5-liter V8 engine and a S65 powered by a 6.0-liter twin-turbocharged V12 rated at 621 ponies.

The Mercedes-Benz S-Class Cabriolet will be fully unveiled online in the days leading up to its public debut in Frankfurt. Stay tuned, we’ll bring you live pics of the first-ever S-Class Cabriolet straight from the show floor starting on September 15th.