The images were first published by Dutch car blog Autogespot, described as "official photos by McLaren".
Said to be a lighter and more powerful version of the 675LT, it’s claimed the car has been brought to life by the McLaren Special Operations (MSO) department as a one-off customer project.
Despite the talk of a one-off plan, however, Autogespot claims it has reason to believe the vehicle will see a limited run of 25 units.
Using the company's power-based nomenclature as a guide, reports suggest the car will make 688bhp (506kW) using the same twin-turbo 3.8-litre V8 engine that powers the 675LT and other McLaren models.
Other apparent enhancements over the 675LT include a large rear wing, a redesigned rear diffuser and twin winglets fixed to the front bumper.
It’s also claimed that thanks to the aerodynamics package, slight power increase and weight-shedding efforts, the 688HS will boast a slightly sharper 0-100km/h time than the 675LT’s 2.9-second claim.
The 325km/h top speed of the 675LT is said to remain unchanged in the supposed higher-spec car, however.
Above: The McLaren 675LT - the supposed basis for the 688HS
McLaren, for its part, is keeping quiet on the leaked vehicle's identity and purpose.
Speaking with CarAdvice this week, McLaren Automotive global public relations manager, Dave Eden, said: “No details [available], other than to confirm that McLaren Special Operations is currently working on a customer project based around the Super Series platform.
"This is a bespoke project which will not become a series production model; the details of which are confidential at this stage. Further details will be confirmed further in to the project.”
Stayed tuned to CarAdvice for more news on any future McLaren products.
Leaked images courtesy of Autogespot.