While Ford's tie-up with the Red Bull team had been anticipated for a while, with Motorsport.com revealing the possibility back in December, the situation regarding AlphaTauri had been less clear.
With current supplier Honda having registered its interest in producing a power unit for the 2026 regulations, there had been speculation it could do something exclusively with AlphaTauri.
But, as Ford finally confirmed its partnership with Red Bull Powertrains during a press conference in New York on Friday, the American car giant made clear its deal would be with the energy drink giant's two F1 squads.
The company is to become a partner in Red Bull Ford Powertrains, to supply its two teams from 2026 until at least 2030.
Work is to start immediately with Red Bull in helping develop the new engine, which will include a 350kW electric motor.
It is anticipated that Ford will assist in the progress of the combustion engine development, as well as in areas like battery cell, electric motor technology, plus other software elements.
Red Bull team boss Christian Horner believed the Ford partnership was a big boost to his squad's long-term ambitions.
"It's fantastic to be welcoming Ford back into Formula 1 through this partnership," he said.
"As an independent engine manufacturer to have the ability to benefit from an OEM's experience like Ford puts us in good stead against the competition.
"They are a manufacturer rich in motoring history that spans generations. From Jim Clark to Ayrton Senna and Michael Schumacher, the lineage speaks for itself.
"For us as Red Bull Powertrains to open the next chapter of that dynasty, as Red Bull Ford, is tremendously exciting."
Ford President and CEO Jim Farley added: "Ford's return to Formula 1 with Red Bull Racing is all about where we are going as a company– increasingly electric, software-defined, modern vehicles and experiences.
"F1 will be an incredibly cost-effective platform to innovate, share ideas and technologies, and engage with tens of millions of new customers."