Are you ready for in-car billboards?

General Motors' partnership with AT&T to add 4G connectivity to its vehicles by 2015 will net streaming videos for back-seat passenger, but could also provide an added revenue stream for the Detroit automaker.

During a conference call on Thursday GM CEO Dan Akerson called the addition of 4G connectivity to its vehicles a "revenue-generating opportunity." GM will launch its first 4G connected vehicles next year, with the technology scheduled to spread throughout the automaker's lineup in 2015.

Akerson said GM will pocket a $20 fee from AT&T for every connected vehicle it sells, and GM and AT&T will also split shared revenue from ongoing services. However, that could just be the tip of the iceberg.

"With a 4G pipe into a car, you can change the business model almost entirely," Akerson said, according to Motoramic. "You may be able to have a real revenue generating opportunity into the car with - when you come up for example, what happens if when the logo shows on your screen and its brought to you by Allstate?"

GM has yet to confirm if it has any real plans to turn its MyLink infotainment system into a rolling billboard, but it appears as though the days of in-vehicle advertising are quickly approaching.