Probably one of the worst kept secrets of last year was that the new ‘F10’ BMW M5 was going to be offered with a regular six-speed manual transmission, though only for North America.

Today, at the 2012 Detroit Auto Show, the manual-equipped M5 has made its official debut.

The car will be introduced as the 2013 BMW M5 and hits showrooms late this summer.

And, as expected, the manual option will only be offered in North American markets. It will be a no-cost alternative to the standard seven-speed M-DCT dual clutch gearbox offered on overseas models.

According to BMW, the manual gearbox was a popular choice for U.S. customers of the previous generation M5, which is one of the reasons it has been offered yet again. You’ll note that BMW’s North American customers also benefit from the manual option on the 6-Series coupe, while overseas customers miss out.

Though the six-speed manual has one less gear than the M-DCT transmission, the ratios have been optimized for acceleration, flexibility and fuel economy. It also has a short throw shift linkage, and comes topped with a black leather backlit shift knob. Importantly, the final drive ratio and special M differential are maintained.

Otherwise the manual and M-DCT M5s should be much the same, both of them running BMW M’s latest TwinPower V-8 engine rated at 560 horsepower and 502 pound-feet of torque. With the M-DCT 0-60 mph acceleration takes around 4.4 seconds and top speed comes in at 190 mph with the optional M Driver's Package.

No performance figures have been released though expect the M-DCT to offer slightly faster acceleration and better mileage. Final numbers should be released closer to this summer’s launch. 

Look out for the 2013 BMW M5 at this week’s Detroit Auto Show and stay glued to our dedicated show page for all the latest updates. And for all the details on the new M5, click here.