NEW YORK — AT&T and an investment firm run by former News Corp. executive Peter Chernin have formed an online video venture that could rival Netflix and Hulu.

AT&T Inc. and Chernin Group said Tuesday that they have committed more than $500 million in funding toward the venture. They are not saying how much each company is investing.

The move comes amid rapid growth in online video services. AT&T, a telecoms giant, already offers TV content through its U-Verse service, which competes with more traditional cable TV providers. With online video, though, it could attract customers of Netflix, Hulu, YouTube and other services — including people who’ve stopped paying for traditional broadcast, cable or satellite TV.

The companies said the venture will invest in advertising and subscription-based video-on-demand services, as well as online streaming.

AT&T rival Verizon Communications Inc. is planning similar services. The telecommunications giant bought Intel Media earlier this year. The onetime division of chip maker Intel Corp. had been preparing to launch a service that streams TV channels over the Internet.

Dish Network Corp., meanwhile, struck a deal with Disney last month that paves the way for the satellite TV service to live-stream Disney-owned channels like ESPN and ABC over the Internet to customers’ smartphones, tablets, video game consoles and other devices.

None of companies have announced start dates for the planned online video services.

The Chernin Group, run by former News Corp. Chief Operating Officer Peter Chernin, is contributing its assets to the venture, including its majority stake in Crunchyroll, a subscription-based provider of anime videos.

In a related development, AT&T said Monday it plans a major expansion of super-fast Internet services to cover as many as 100 municipalities in 25 metropolitan areas.

The service, called GigaPower, has a 1 gigabit per second speed that is about 100 times what U.S. consumers typically get with broadband. That means faster video downloads and the ability for more devices to connect to the network without congestion.

AT&T currently has such speeds in Austin, Texas, and has committed to offer the service in Dallas. The company is also in advanced talks to bring GigaPower to two additional markets, Raleigh-Durham and Winston-Salem, N.C.

A rival offering from Google Inc., known as Google Fiber, is available in Kansas City and is coming soon to Austin and Provo, Utah. Smaller companies and public utilities offer or plan such speeds in a handful of other markets throughout the U.S.

AT&T Inc. said Monday that the specific number of markets beyond its initial four will depend on discussions with local officials and assessments of potential demand. The company said it may start building some of the new networks by the end of the year.

None of the new markets are in the Northeast because AT&T doesn’t have landline operations there. Verizon serves much of that area and has been offering its own fiber-optics service, FiOS, though its top speed is at half of what AT&T is planning.