Infiniti is reportedly planning a new concept for the 2018 Detroit motor show in January, previewing a potential rival for the Lexus LS and Mercedes-Benz S-Class.

Speaking with Car and Driver, Alfonso Albaisa, Infiniti's design boss, said the company is planning some "news" for the Detroit event when asked about the possibility of a new flagship luxury sedan.

"In Detroit, we will show something about that subject which is super nice," he said, "the straight sedan is losing a little bit of appeal again."

The head of design indicated this new model would look less like a traditional sedan and more like a four-door coupe.

"Honestly, we have a little bit of a new proportion because of new technologies, and without saying too much, we will have some news in Detroit," he added.

It has been over a decade since Infiniti last offered a full-size sedan, as the V8-powered Q45 went out of production in 2006, though the Chinese market does get the Q70L - a long-wheelbase version of the mid-size sedan.

However, the company did show the Q80 Inspiration concept (pictured) at the 2014 Paris motor show, which took the form of a four-door coupe with suicide doors, and a more dynamic focus.

With that in mind, a production version of such a vehicle would be more driver-oriented - a-la BMW 7 Series, Jaguar XJ and Porsche Panamera - as opposed to the Mercedes-Benz S-Class and Lexus LS.

In 2014 when the Q80 Inspiration was revealed, product planning manager for Infiniti Cars Australia, Bernard Michel, told CarAdvice the concept did indeed preview a production model.

"You can’t be a luxury brand without halo models, right? So this is where the brand is going," he said.

"It will be a sports-type, as opposed to a more luxury-type car."

Funnily enough, just about every Infiniti concept since the Q80 Inspiration spawned a production model - think Q30, Q60, QX50, QX80 - and all have stayed relatively close to the show car preview too.

Above: Infiniti Q60 concept

Stay tuned to CarAdvice for our coverage of the 2018 Detroit motor show.