The closely held rocket launch company, of which Musk is founder and chief executive officer, made the payment in 2018 to an unidentified flight attendant who worked as a contract employee on a SpaceX corporate jet, the online news provider said, citing interviews and documents, including a declaration signed by a friend of the attendant and made in support of her claim.

In late-night tweets responding to a follower, Musk said: “For the record, those wild accusations are utterly untrue.” He then called the source of the story a “liar” and said the incident never happened. In an earlier tweet that didn’t directly refer to the Insider report, Musk said “the attacks against me should be viewed through a political lens” but that nothing will deter him from fighting for “your right to free speech.”

The billionaire, who since announcing his $44 billion bid for Twitter Inc. has promised to make it more of a free-speech platform, on Thursday said he’s given up on Democrats and will now vote Republican. The attendant alleged that Musk exposed himself and propositioned her in a private room on the plane during a flight, according to the friend, the report said. Musk offered to buy the attendant a horse in exchange for an erotic massage, it said. Representatives for Hawthorne, California-based Space Exploration Technologies Corp. didn’t immediately reply to a request for comment.