You may some day be able to get a solar roof on your Tesla.

On Friday, CEO Elon Musk tweeted that the company would likely begin to include solar roofs as an option for its cars. Musk didn’t share a specific timeline of when to expect the feature, but he did say in a follow-up tweet that it wouldn’t be too expensive.

Musk has been hinting at the possibility of Tesla building cars with solar roofs for some time.

After the unveiling of Tesla's solar glass shingles last Friday, Musk tweeted that the same glass technology could be used on the roof of a car to act as a defroster. Musk also added that solar glass on a car would be net positive, meaning that it would create more energy than it used to do things like defrost the hood of the vehicle.

During a conference call on Tuesday, Musk said that Tesla had formed a new glass technology group and that they were working to develop a special glass for the Model 3, which is Tesla's first mass market car.

The Model 3, as you can see in the picture below, incorporates a lot of glass into the design.

Tesla Model 3

Foto: Tesla Model 3 source Tesla Motors

Tesla seems to be moving in this direction in general with the design of its cars.

The Model X has a panoramic glass roof that covers the entire front end of the vehicle. And earlier this week Tesla quietly rolled out a new all-glass roof option for its Model S.

The new glass roof for the Model S doesn't appear to have any special solar functions, but the design change certainly suggests that Tesla is looking to incorporate its solar glass tech into more vehicles.