Last week we spotted the SL63 AMG undergoing some Nurburg ring time in Germany, the car was lapping with the standard SL so was easily missed.

Although still covered in camouflage, these pictures prove that Mercedes-Benz have officially begun final testing of the next-generation SL63 AMG, which will be on the market in 2012 or 2013.

Underhood we expect to see Mercedes new 5.5L twin-turbo V8, generating around 570 horsepower. Distributing the power to the rear wheels will be the Speedshift MCT seven-speed transmission from AMG.

Look closely and you’ll see large air ducting and a more sugestive fascia leering out from behind the camouflage. Performance brakes with cross-drilled floating rotors are clearly visible, although Mercedes has hidden the SL AMG’s exhaust outlets to look like those found on the normal SL.

Expect a teaser at the Frankfurt Motorshow in 2010 before the likely full release in 2011.