General Motors Co. reached a deal Thursday to gain access to Tesla Inc.'s network of electric vehicle chargers, joining its crosstown rival Ford Motor Co. in an industry-changing tie-up intended to speed consumer adoption of battery-powered vehicles.

By turning the EV market leader from foe to friend, both of the Detroit automakers are adding to Tesla's overwhelming lead in the number of public fast chargers in the United States — a critical component in the auto industry's historic transition from gas and diesel engines to electric motors. The lack of enough reliable public chargers has been one of the biggest hurdles to EV adoption among American motorists.

"I think we have a real opportunity here to really drive this to be the unified standard for North America, which I think will enable more mass adoption," GM CEO Mary Barra said during a live event with Tesla CEO Elon Musk announcing the partnership on Twitter Spaces, which is part of the Twitter social network owned by Musk, "so I couldn't be more excited."

Automakers, including GM and Ford, have been using the Combined Charging System (CCS) standard on their electric vehicles. Tesla created its own connector and last fall offered up its design to everyone, inviting "charging network operators and vehicle manufacturers to put the Tesla charging connector and charge port, now called the North American Charging Standard (NACS), on their equipment and vehicles," the automaker said in a November blog post. Tesla says its connector is "half the size, and twice as powerful" as the CCS connectors.

Ford took Tesla up on its offer two weeks ago when Musk and Ford Motor Co. CEO Jim Farley announced their alliance, also during a live event on Twitter Spaces. Starting next year, Ford's EVs will gain access to Tesla's Supercharger network with a Tesla-developed adapter.

That arrangement will give Ford customers access to more than 12,000 Superchargers, more than doubling the number of EV fast chargers they currently can use.

"We're ramping production and we think this a huge move for our industry and for our all-electric customers," Farley said during the May 25 announcement. "Widespread access to fast-charging is absolutely vital to our growth as an EV brand."

The Charging Interface Initiative, CharIN, a global association focused on the electrification of all forms of transportation enabled by CCS and the Megawatt Charging System, responded bluntly to the Ford/Tesla partnership: “CCS is the global standard and therefore focuses on international interoperability and, unlike NACS, is future-proofed to support many other use cases beyond public DC fast charging.”

Musk on Thursday's call with Barra hailed the GM-Tesla partnership as a step toward greater EV adoption in the United States.

"This will really help put people's mind at ease and focus on one standard," he said. "And it's really going to be great for consumers. They just won't have to worry about which plug, which socket, which charging station. It'll just work seamlessly."

Current GM owners will be able use the superchargers starting next spring with an adapter. GM did not specify what company will be manufacturing the adapters.

And starting in 2025, the first GM EVs will be built with a NACS connection and will not have a CCS connection.

GM added that in the future it will make adapters available for drivers with the NACS-enabled vehicles to allow charging on CCS-capable fast charge stations.

Tesla has about 1,800 fast-charger stations with more than 19,400 charging ports in the U.S., which is more than the 10,130 CCS-capable ports at about 5,200 locations, according to data from the U.S. Department of Energy's Alternative Fuels Data Center.

“GM needed to make this move as they’re diving into the deep end of EVs,” said Dan Ives, an analyst with investment firm Wedbush Securities Inc. “The Ford-Tesla partnership put more pressure on Barra to go ahead and finally foster that partnership with Tesla.”

The major obstacles to EV adoption include range anxiety, which is amplified by an insufficient charging network. With that not being built out fast enough for GM’s rollout, plus its crosstown rival's deal with Tesla, GM had to act.

“This is a key time for GM to lay down the groundwork from delivery to battery technology,” Ives said. “But the missing piece is the charging network. Tesla has it. GM needs it. That’s why that call ultimately went to Musk.”

Although that could mean Tesla owners will face increased competition from other EV drivers for available chargers, the deal is “another notch on the belt for Musk,” Ives said.

“I think Tesla is drinking champagne as Detroit stalwarts call and need their charging stations,” he said. “It enables them to monetize the supercharger network.”

Other EV producers, meanwhile, are likely weighing the decision to partner with Tesla after two of the Detroit Three automakers took the leap.

"It's entirely possible that other automakers will be looking at the scenario and trying to figure out whether or not it works for them," said Stephanie Brinley, an associate director at S&P Global Mobility. "If they weren't thinking about it before, they're going to be thinking about it now."

Brinley noted that "this will even itself out" and by 2030 or 2035 a standard should be solidified.

"It's important to remember that we're talking about a transition and a transformation that's going to take us 15 years," she said. "As that happens, it's fairly natural to see an evolution and to say, 'OK, this connector works, that one is less good, this one's better' ... we've seen that in a number of different spaces."