Tesla Chief Executive Elon Musk says he once considered selling the electric car maker to Apple, but the iPhone maker’s CEO blew off the meeting.

In a tweet Tuesday, Musk said he reached out to Apple CEO Tim Cook “to discuss the possibility of Apple acquiring Tesla (for one-tenth of our current value). He refused to take the meeting.”

Specifically, Musk wrote in a tweet on December 22:

“During the darkest days of the Model 3 program, I reached out to Tim Cook to discuss the possibility of Apple acquiring Tesla (for 1/10 of our current value). He refused to take the meeting.”

Tesla’s market value is US$616 billion, as of the close of trading Tuesday. One-tenth of that is US$61.6 billion.

Musk said he sought out the meeting with Cook “during the darkest days of the Model 3 program,” a reference to Tesla’s first electric car designed for the mass market. As recently as 2018, Tesla was struggling to meet its vehicle production goals and turn a profit.

Tesla’s fortunes have changed since then. The automaker is finally making money on a consistent basis after years of losses and continues to hit milestones for deliveries of its vehicles. Its shares have soared 665 percent this year alone, making it the world’s most valuable automaker and among the top 10 biggest U.S. companies in the S&P 500 index, which Tesla entered on Monday.

Musk’s tweet followed published reports suggesting Apple is working on developing its own electric cars.

Apple declined to comment.

On Tuesday, Musk also made remarks about lithium iron phosphate batteries that Apple is reportedly developing for use in vehicles, per a Reuters report on Monday.

“Strange, if true,” Musk wrote. “Tesla already uses iron-phosphate for medium range cars made in our Shanghai factory.- A monocell is electrochemically impossible, as max voltage is ~100X too low. Maybe they meant cells bonded together, like our structural battery pack?”

It was a rare admission from the mercurial CEO that he once considered giving up control of the company he helped build and take to a market value that’s more than the top nine automakers combined. Tesla has not discussed a sale in any financial filing.-AP/CNBC

Apple Chief Executive Tim Cook speaks at the Apple Worldwide Developers Conference in San Jose, Calif. In a tweet Tuesday, Tesla CEO Elon Musk said he once considered selling the electric car maker to Apple, but Cook blew off the meeting

Apple stays mum on Elon Musk claim of spurned approach to sell Tesla