Inline-six engines aren't exactly the most common configurations around. However, it does look like it's making a comeback. BMW aside (who swears by the straight-six configuration), Mercedes-Benz reintroduced the classic configuration about a year ago. Now, it's Jaguar and Land Rover who have followed suit.

It's a particularly significant moment for Jaguar  as it marks the return of the straight-six in their vehicles after 23 years. This year also marks the 71st anniversary of Jaguar's first series production inline-six engine, which was used in the XK120. Land Rover on the other hand has never used an inline-six engine prior to this announcement, so this will be a first for them.

Straight-six comeback: Jaguar-Land Rover releases all-new inline-six engine image

So what's the all-new Jaguar-Land Rover inline-six engine like? It has a displacement of 3.0-liters, which is a pretty common affair in the luxury vehicle market. What makes the engine unique among its competitors is the fact that it's both turbocharged and surpercharged. In fact, the engine is actually part of a new hybrid system that will power more models in the future. Yes, this powertrain is electrically assisted.

Paired to the engine is a 48v battery pack. With electric assist, the combined output is rated at 400 PS and 550 Nm of torque. Also, the electric motor helps drive the engine's supercharger, ensuring as little lag as possible. Now, this isn't a full hybrid system as that role is reserved for the plug-in models. The inline-six and electric motor combo is a mild hybrid system.

Straight-six comeback: Jaguar-Land Rover releases all-new inline-six engine image

The first vehicle that will get the all-new powertrain is the Land Rover Range Rover Sport with the new HST trim level. Despite the 4x4's hefty curb weight and 400 PS output, Land Rover says that it can do the 0 to 100 km/h sprint in 6.2 seconds, can reach a top speed of 225 km/h, but can still return up to 10.75 kilometers per liter in mixed driving. As for Jaguar, they have yet to announce which car they will choose to have this mild-hybrid powertrain.