Spy shots of the 2021 Rolls-Royce Ghost Extended Wheelbase.

When it comes to Rolls-Royce sedans, it's best to sit behind the wheel, not behind it. Let the driver worry about traffic.

That's why space and comfort in the back seats are paramount in an ultra-luxury Rolls-Royce. That's why the Ghost, already one of the largest sedans on the market, has an extended version, which Rolls-Royce calls "extended wheelbase."

The British automaker is developing an updated Ghost. It is expected to arrive around the end of the year and likely in 2021.

Now we've gotten spy shots of a prototype of an extended version, namely the new Ghost Extended Wheelbase. It should arrive shortly after the standard model.

Like its predecessor, the new Ghost Extended Wheelbase is about 6.0 inches longer than the standard model, with much of that length benefiting rear-seat passengers. The extended rear doors are clearly visible on this prototype.

The platform uses Rolls-Royce's own aluminum spaceframe, which debuted in 2017 with the latest Phantom. The lighter weight design compared to the platform it replaces should provide improved dynamics and efficiency for the new Ghost range.

The same 6.75-liter twin-turbo V12 twin-turbo as on the Phantom and Cullinan will be used as the powerplant, producing 563 hp and 664 lb-ft of torque, the latter at a low 1,700 rpm with an eight-speed automatic transmission. Mated to the rear wheels, the V12 engine should propel the car to 60 mph in less than 5.0 seconds and a top speed of 155 mph. Electrification in one form or another is likely to be introduced at a later date.

Naturally, the interior will be characterized not only by luxury, but also by high technology. This will include surround-view cameras, night vision, adaptive cruise control, frontal collision warning system, lane crossing warning system, lane departure warning system, Wi-Fi hotspot, and head-up display.

The Wraith and Dawn should eventually be replaced by new Ghost coupe and convertible models.