The Cadillac CT6 may have been dropped in the U.S. after 2020 but it remains on sale in China, and a new prototype sighting suggests a redesigned version is on the way.

Cadillac engineers have been spotted testing a new full-size sedan believed to be a successor to the CT6. The prototype was spotted testing on U.S. soil, but it's unlikely the car will be offered outside of China, where sedans still sell in significant numbers.

Look for it to be launched in that market sometime in 2023.

The new sedan looks similar in size to the current CT6, which measures 205.8 inches in length. But instead of the traditional notchback design of the CT6, the new sedan adopts a curved roof with a fastback design.

2023 Cadillac CT6 spy shots - Photo credit: S. Baldauf/SB-Medien

2023 Cadillac CT6 spy shots - Photo credit: S. Baldauf/SB-Medien

Underpinning the car is thought to be General Motors' VSS-R rear-wheel-drive platform. It's a member of the VSS (Vehicle Strategy Set) portfolio of platforms designed for internal-combustion vehicles, and replaces both the Omega platform of the CT6 and Alpha II platform of the smaller CT4 and CT5 sedans.

Completing the VSS portfolio is a VSS-F platform designed for mini and subcompact vehicles with front-wheel drive, a VSS-S platform for small and mid-size vehicles with front-wheel drive, and a VSS-T platform for body-on-frame vehicles.

The CT6 is offered in China with the choice of 2.0-liter turbo-4 or twin-turbo 3.0-liter V-6 powertrains, or a plug-in hybrid setup using the 2.0-liter engine as its internal-combustion component. Expect the new sedan to arrive with a similar spate of powertrains.

But what about an electric sedan from Cadillac? The automaker is planning one, including for the U.S. It's called the Celestiq, and it's a giant hatchback based on GM's Ultium EV platform and battery set. It's expected to go on sale in 2024 as a 2025 model, and be priced in Bentley and Rolls-Royce territory.