The $1.6 billion plant, to be built in an unspecified US location and open in 2021, will be able to produce 300,000 vehicles a year and employ 4,000 people, Reuters reported.
The prospect of a new factory in the US could set off a competition among states over its location.
The deal could further cement President Donald Trump's vision of bringing more jobs to the US.
Aside from building the new USA plant, the companies will look to jointly develop technology for electric vehicles and connected cars, as well as collaborate on advanced safety technology.
The deepening ties between Toyota and Mazda also are driven in part by the enormous costs automakers are facing to develop connected, self-driving and battery-powered vehicles.
The new plant will be responsible for building the Toyota Corolla, which was originally planned to be built at Toyota's new plant in Mexico alongside an unnamed Mazda model.
However, Toyota now says the said production will shift to the US.
Lentz said he could not say what impact Trump's comments had on a decision that was under consideration for some time with Mazda because it was a decision made by executives at both vehicle companies in Japan.More news: United States military says is conducted 'successful' THAAD missile test over Pacific Ocean
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Toyota has plants in Indiana, Kentucky and Texas.
Toyota has sold more than 10 million hybrid gasoline-electric vehicles globally, including the Prius, since 1997.
"There will be no substantial impact on Toyota's investment and employment plan there", the Japanese auto manufacturer said.
"Mazda has been studying the Toyota Production System, with direct help from Toyota, since the 1970s", said Shook, a former Toyota engineer. "Because of its strong dependence on North American market, Mazda absolutely needs to expand its manufacturing footprint here".
For Toyota, the investment is a push to expand USA vehicle-making capacity and market share and intensify its attack on the Detroit automakers' lucrative truck business.
It also gets a boost in electric cars. "The plant will require a total investment of approximately 1.6 billion USA dollars, and will create up to 4,000 jobs", the press release said.
According to Reuters, Mazda, who has sales are one eighth of Toyota's, only has a research budget of 140 billion yen per year - compared to Toyota's one trillion yen.
Toyota, which has been vying against the Japan-France alliance of Nissan-Renault, Volkswagen AG of Germany and US manufacturer General Motors Co. for the spot of world's No. 1 automaker, stuck to its earlier projection for global vehicle sales for the fiscal year at 10.25 million vehicles.