BMW got a lead over its rivals when it put a coupe roofline on the large X5 SUV and called it the X6 a few years ago, so now the competition is playing catch-up. One of the latest, and perhaps most eagerly awaited newcomers to the SUV coupe genre, is the upcoming Porsche Cayenne coupe. And completely unsurprisingly it's now been spotted undergoing testing at the Nurburgring in Germany.

As well as being an obvious threat to the BMW X6, the new Cayenne coupe will also take aim at the Mercedes GLE coupe. When BMW first came up with the SUV coupe concept it was met with more than a little derision from some quarters, but buyers have taken to the new segment in considerable numbers and now it seems every manufacturer is getting in on the act.

The current Cayenne lineup is relatively limited as there's just one body style with a choice of petrol and hybrid powerplants. The coupe version will therefore expand the offering, and considering the appeal of the Porsche brand, this is a model that's going to be in considerable demand. However, if you're hanging back from purchasing your next vehicle because you're waiting for the Cayenne coupe, you're going to be waiting for a while yet because it's not expected to come to market until towards the end of 2019.

Images of prototypes being put through their paces at the Nurburgring published by show the new model inherits the same front-end styling as the third-generation Cayenne, apart from a front bumper that appears to be a unique design for this model to help differentiate it from the rest of the Cayenne range. This new variant also adopts a suitably more sporty overall style with a liftback-style tailgate, a new tail light design, and new side windows to accommodate the sloping roofline.

A retractable rear spoiler is another unique design cue for this model as it seems to be a single piece instead of the split wing design we see already with the second-generation of the Panamera.

In keeping with its sporty styling, the Cayenne coupe will be a genuine performance model. Under the hood will be a choice of a 440bhp twin-turbo 2.9-liter V-6 and a 4.0-liter V-8 twin-turbo boosting 550 horsepower. Perhaps not surprisingly in the current climate, there's no diesel variant of the Cayenne coupe planned.