Tesla brushed off an offer last year by Uber to partner on self-driving cars.
The revelation comes from Wild Ride, a book written by Fortune's Adam Lashinsky, which Bloomberg read in advance of its publication next week.
Uber CEO Travis Kalanick pitched the partnership idea to Tesla boss Elon Musk, who said the idea was "too far out" and that Uber should continue focusing on its core ride-hailing platform, according to Bloomberg.
A few days after turning Kalanick down in the summer of 2016, Musk said he planned to enter the ride-hailing business, effectively competing with Uber.
Uber declined to comment on the matter. Tesla did not immediately return Business Insider's requests for comment.
"When true self-driving is approved by regulators, it will mean that you will be able to summon your Tesla from pretty much anywhere," Musk wrote in his "Master Plan, Part Deux" last year. "You will also be able to add your car to the Tesla shared fleet just by tapping a button on the Tesla phone app and have it generate income for you while you're at work or on vacation, significantly offsetting and at times potentially exceeding the monthly loan or lease cost."
Tesla plans to operate its own fleet in cities where demand exceeds supply, Musk wrote in the plan. The electric carmaker plans to release more details about its ride-hailing service, Tesla Network, at some point this year.
Tesla cars are currently being built with the hardware to eventually support fully autonomous driving.
Musk's declared entrance into the ride-hailing space marked a stark departure from his previous stance on car-sharing. In 2014, Musk said there's "a limit to the whole sharing thing."
Whether or not Kalanick's proposal played a role in inspiring Musk to seriously pursue car-sharing is unclear. But Kalanick said in Wild Ride he knew Musk was planning to compete when he turned down the offer.
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