For those looking at buying the 4.4 litre twin-turbo V8 BMW 7 Series, fuel economy might not be high on the list of priorities.

However, for Bimmer drivers who like to have their cake and eat it too,  BMW has been busily preparing a hybrid version of its flagship sedan.

Reports now suggest that the production version of the 750Hi will make its debut at the Frankfurt Motor Show come this September.

In full-tilt petrol chugging mode, the 4.4 litre is good for around 300kW (400hp) and, while it’s been said the electric portion of the system will only add another 15kW (20hp), the real boon will be in the torque department.

Nothing has been confirmed just yet, but it’s been suggested that torque output could be as high as 810Nm (591 lb-ft) when both motors really get going.

Fuel economy figures are nowhere to be seen, but BMW claims a reduction of 20 percent over the petrol only model.

More news should become available as the Frankfurt Motor Show draws near, so stay tuned for further updates.

GALLERY » BMW 7 Series ActiveHybrid Concept