Mercedes-Benz's iconic SL is currently into its sixth generation, with the car's last redesign introduced for the 2013 model year.

A new SL is coming up shortly, only this time it is being developed by the Mercedes-AMG performance skunkworks and not Mercedes-Benz. A prototype has been spotted and is likely for the new SL63 variant.

The clear giveaways that this isn't an entry-level SL are the square-shaped exhaust tips which are normally reserved for the top variants in AMG's lineup. The car also features additional flics for downforce on its front fascia.

2022 Mercedes-AMG SL63 Roadster spy shots - Photo credit: S. Baldauf / SB-Medien

2022 Mercedes-AMG SL63 Roadster spy shots - Photo credit: S. Baldauf / SB-Medien

As for the rest of the exterior, Mercedes design chief Gordon Wagener said the new SL will take the line closer to the original 300SL, but not in a retro way. The latest tester is still heavily camouflaged, though we can make out some of the proportions and finer details.

Under the sheet metal, the new SL will utilize a new rear-wheel-drive platform for sports cars dubbed MSA (Modular Sports Architecture), which AMG will also use for its next GT sports car, meaning we can expect a much more performance-focused SL this time around. Less weight will be key. Expect the use of lighter, more exotic materials in the construction, as well as a soft-top roof in lieu of the retractable hard-top of the past two generations.

There will likely be two variants at launch, both with mild-hybrid powertrains. One is likely to be badged an SL53. The other is the SL63 you see here.

2022 Mercedes-AMG SL63 Roadster spy shots - Photo credit: S. Baldauf / SB-Medien

2022 Mercedes-AMG SL63 Roadster spy shots - Photo credit: S. Baldauf / SB-Medien

The SL53 is expected to pack a 3.0-liter turbocharged inline-6 and mild-hybrid system for a combined output of around 430 horsepower. The SL63 should feature a 4.0-liter twin-turbocharged V-8, together with a mild-hybrid system for a combined output over 600 hp.

Don't expect a V-12 to return. Instead, we may see the SL63's V-8 paired to a more powerful electric drive system in a plug-in hybrid model potentially dubbed the SL73e. Such a system has already been previewed in concept form and is set to debut soon in AMG's GT 4-Door Coupe. Output for this system could be over 800 hp.

Look for the new SL to debut in 2021 as a 2022 model. The car will fill in for the S-Class Coupe and S-Class Convertible which are being dropped at the end of the 2020 model year. The two-door S-Class models are among seven models reportedly facing the ax as part of major cost-cutting measures at Mercedes.