The images, first published by Japan's Best Car magazine, reveal the front and rear of the blue prototype almost completely free of camouflage. Tellingly, the only parts of the car that are disguised are the badges, and Lexus’ distinctive ‘F’ badge can clearly be made out beneath the black tape in the rear-end shot.
The new images come five weeks after a seemingly identical silver Lexus GS F prototype was spied in a garage in Germany.
Distinguishing the high-performance duo from the standard GS is a carbonfibre boot lid lip spoiler and a matching lower skirt with stacked quad exhaust outlets. The pair also wears the same multi-spoke grey alloy wheels.
The latest shots also reveal the GS F prototype’s front end, which sports assertive angular air intakes underpinned by carbon skirts, while aggressive vents behind the front wheels are expected to aid cooling and air flow.
The grey carbonfibre theme also appears to extend to the wing mirrors and exterior door handles.
Best Car also generated a rendering (above) from the spy shots, painting a seemingly accurate picture of what to expect from the highly anticipated luxury performance sedan.
The magazine also list a speculative 465PS (342kW) power figure for the GS F’s 5.0-litre V8, which would give it a healthy advantage over the current 311kW Lexus IS F sports sedan but leaving it some way behind the likes of the updated M5 (423kW), the new Audi RS6 (412kW) and the refreshed Mercedes-Benz E63 AMG (430kW).
A spokesman for Lexus Australia said he had no information on the prototype.
Reports have suggested the production version of the Lexus GS F could be unveiled as early as next year.