Design cues for the company's crucial sedan rival for the likes of the Audi A4, BMW 3 Series and Mercedes-Benz C-Class, as expected, will come from the Lexus LF-CC concept car (main image) from the 2012 Paris motor show.
The LF-CC was a preview of a new coupe version that will expand the IS range, likely from 2014.
The coupe concept featured a hybrid drivetrain combining a 2.5-litre V6 and an electric motor that will form the basis of a Lexus IS300h model. The hybrid will replace the diesel engine offered in the outgoing IS in Europe.
The sedan is also expected to use the same 2.5-litre V6 and 3.5-litre V6 found in the bigger GS large car to again create Lexus IS250 and Lexus IS350 models.
An F Sport variant can also be expected to be among the variants considering the success of the badge that indicates the more sport-focused models in Lexus's different vehicle ranges.
The new IS will share its platform with the GS.
Lexus has yet to confirm whether it will build its other coupe concept, the LF-LC (above) that also starred at this year's Sydney motor show, but the company's upcoming compact SUV is expected to be unveiled in 2013, possibly at March's Geneva motor show.
The 2013 Detroit motor show kicks off with media days on January 14 and 15.