Bentley's twin-turbo 6.0-liter W12 will be permanently retired in a year's time, but until such time as the luxury marque is ready to go all-electric, it needs a contingency, which is why it is developing a new plug-in hybrid V8 powertrain for use in the Flying Spur Hybrid. Our spy photographers have snapped Bentley's development team testing vehicles in the icy European winter, including the refreshed Continental GT and the new Flying Spur Hybrid. While the W12 was an engine completely unique to Bentley, the new powertrain is expected to be shared with Porsche.

The new engine will likely accompany an upcoming facelift, which seems to be the case as this test prototype has a new bumper design not shared with the current model. The exhaust pipes are also different and are more similar to those found on the Flying Spur Speed. While these design elements may not necessarily hint at a new powertrain, our spies say the engine did not sound like a V6 at all but rather had the deep rumble of a V8.

This is likely the same 4.0-liter twin-turbo V8 paired with a PHEV system found in the Porsche Panamera Turbo S E-Hybrid.

It would make complete sense, given that Bentley and Porsche fall under the Volkswagen Group umbrella. With the bigger engine and electrical assist, the Flying Spur can produce upwards of 690 horsepower and 641 lb-ft of torque. Comparatively, the Flying Spur V6 PHEV makes 536 hp and 553 lb-ft of twist, while the outgoing W12 has 626 hp and 664 lb-ft on tap. Dropping in that V8 PHEV combo into the Flying Spur and other Bentleys, including the Continental GT and Continental GTC convertible, makes a lot of sense.

Unfortunately, we don't know the launch dates for either model, but the more powerful V8-powered versions with electrical assistance are definitely on the way. The Flying Spur V8 PHEV will not rival the Panamera Turbo S E-Hybrid but rather the Rolls-Royce Ghost, which lacks a PHEV option.

Right now, the Ghost only comes with a 6.75-liter twin-turbocharged V12 producing 563 hp and 627 lb-ft. However, it's unlikely that Rolls-Royce will respond with a V8 of its own. The brand has committed itself to electrification and has already revealed the fully-electric Spectre with 577 hp. The Ghost will likely be replaced with a BEV, and the brand has no plans for a hybrid changeover period.

Bentley's electrification plans see it becoming an EV-only brand by 2030, so these PHEV options are merely stop-gap measures. But at least the V8 PHEV will offer W12 power levels in the Flying Spur for the next few years until its inevitable electric replacement.

If we had to guess, the Flying Spur and Continental GT and GTC V8 PHEV models will debut either later this year or early next.