As if Elon Musk isn't running enough companies, he once may have suggested taking over as CEO of America's most valuable business, Apple.

Five years ago, in the midst of manufacturing delays and other issues plaguing Tesla's planned Model 3 launch, Musk is said to have had a phone call with Tim Cook during which the Apple CEO proposed buying Tesla. Musk said he'd do it, but on one condition: "I'm CEO." It reportedly took Cook a moment to realize Musk meant taking his job.

That's according to a Los Angeles Times review of "Power Play: Tesla, Elon Musk and the Bet of the Century," a forthcoming book by Wall Street Journal reporter Tim Higgins, who covers Apple, Tesla and other tech companies. The review, published Friday, adds that Cook reportedly responded to Musk with an expletive and hung up the phone.

For their part, Musk and Cook have denied ever speaking to one another.

In December, Musk revealed on Twitter that he had considered selling Tesla to Apple but said he never actually talked with Cook. Replying to a report about Apple's plans to release a battery-powered, mass-market automobile, Musk said he reached out to Cook during the "darkest days of the Model 3 program" about acquiring Tesla "for 1/10 of our current value."

"He refused to take the meeting," Musk said.

Musk also denied that the interaction described in the book happened in a tweet on Friday, following the publication of the book review.

"Cook & I have never spoken or written to each other ever," Musk said, adding that he had once requested a meeting with Cook to discuss Apple buying Tesla, but that it didn't happen and "there were no conditions of acquisition proposed whatsoever."

Higgins, the author, responded to Musk's Friday tweet saying the Tesla founder was given "plenty of opportunities" to comment on the anecdote.

"This anecdote comes from Musk's own account of the conversation, according to people who heard the retelling at the time," Higgins tweeted.

When asked about the book's claims, Apple directed CNN Business to an April interview Cook did with reporter Kara Swisher, who asked about Musk saying he refused a meeting. "You know," Cook responded, "I've never spoken to Elon, although I have great admiration and respect for the company he's built."

Musk and Cook were photographed sitting near one another — with only Oracle CEO Safra Catz between them — in a meeting with former President Donald Trump in December 2016. It's unclear if the two spoke.

"Power Play" is set to be released on August 3.

- by Clare Duffy, CNN Business