Lexus is set to launch a luxurious coupé-cabriolet version of its next-generation LS executive saloon within the next five years, according to company insiders.

Lexus sources see the luxurious sports car as the “car that most captures the essence of what Lexus is all about: performance, luxury and the environment, more so than any Lexus model to date”.

See Autocar's exclusive rendering of the Lexus LC600h

The new coupé-cabrio is being pitched as a successor to the now discontinued SC. Dubbed LC600h and rendered here as a coupé-only, in production it will be a rival for the Mercedes SL, complete with a retractable metal roof.

It will use a shortened version of an all-new platform currently being developed for the next-generation LS, itself due for launch in 2014.

The performance will come from the LS600h’s petrol-electric powertrain, comprising a V8 petrol engine and a hybrid transmission, featuring two electric motors and an epicyclic gearbox. This is the same system that’s also set to find use in Lotus’s luxurious new Elite and Eterne models.

See spy pics of the new Lexus IS and GS models in testing

In the all-wheel drive Lexus, the powertrain will be tuned to produce a combined power output well in excess of 500bhp and be capable of covering the 0-60mph sprint in less than 5.0sec.

Despite the explosive performance, the LC600h should manage a CO2 emissions figure of less than 200g/km and be capable of returning more than 35mpg.

Described as being developed “in the shadows” of the next LS, the LC600h’s chance of reaching production by 2015 looks promising and is only likely to fail should there be another economic global downturn.

“If we don’t get any more nasty surprises on the economic front, then any time after 2015 might be the right moment for the LC,” said a Lexus insider.