There’s a new upcoming member of the ever-growing Porsche 911 family. What you see in the gallery below is a prototype of the 911 ST which will become a special edition model inspired by a small-run racing model from the early 1970s. This is obviously not the final product you’ll see at the company’s showrooms but these new spy photos reveal many of its design features.

You can’t miss the double-bubble roof, for example, that comes straight from the 911 Sport Classic, which was launched earlier this year. This test vehicle doesn’t have a two-colour body and it’s all black, but there could be different colour schemes for the production model that will better underline the roof design, which remains hidden to a certain extent for now. Another feature worth pointing out is the set of centre lock wheels and this shouldn’t come as a surprise since the 911 ST is reportedly based on the Porsche 911 GT3 Touring.

Gallery: Porsche 911 ST new spy photos

Moving to the back, there's a weird black circle on the engine cover's mesh, left from the brake light. We don’t know what it is for sure but our spy photographers report this could be the location for the Porsche Heritage logo, a similar one to the emblem seen on the 911 Sport Classic. Further down the rear fascia, there’s an aggressive diffuser with a centre-mounted pair of exhaust pipes, though this layout appears to be the same as on regular the 911 GT3 Touring.

Logic tells us the powertrain under the rear bonnet will also be shared with the 911 GT3 Touring without modifications. If this assumption is correct, we expect the 4.0-litre flat-six engine to continue producing 502 bhp (374 kilowatts) and 346 pound-feet (469 Newton-metres) of torque. Whether there will be a manual transmission or not, remains to be seen.

The 911 ST is believed to be the second of a total of three heritage versions of the 911 sports car that Porsche wants to launch. The first one was the 911 Sport Classic mentioned above and word on the street is the third one will be a revived version of the Carrera RS. But before it arrives, the 911 ST will have its debut probably sometime next year.