The rivalry between Elon Musk and Jeff Bezos has heated up as the Tesla (TSLA) CEO took what seemed to be an apparent shot at the former Amazon (AMZN) founder when The Washington Post reached out for an interview this week.

Musk and Bezos have had a long-standing history of taking digs at each other and the latest comment from the car genius seemed to be aimed directly at his adversary.

When Musk was contacted to do an interview for the Post’s article, “Elon Musk Moved to Texas and embraced celebrity. Can Tesla Run on Autopilot?” he replied to the new outlet’s request by saying, “Give my regards to your puppet master.”

While Musk didn’t specifically mention Bezos by name, it was apparent that he was most likely referring to him as he owns the Post – a purchase he made in 2013 for $230 million in cash.

Tuesday’s article by the Post’s Faiz Siddiqui discussed Tesla’s move to Texas, with critics claiming that it was “questionable” and the “seeming cult of personality that has developed around him, are beginning to show in the car company he runs."

Siddiqui said he interviewed a dozen current and former Tesla employees, investors, and analysts for the article as well as reaching out to Musk via email.

The Post has repeatedly said that Bezos has no editorial influence over the news outlet.

Musk and Bezos’ feud dates back as far as 2004, Business Insider reported.

The two billionaires have gone head-to-head over a number of issues including their personal wealth.

Over the last few weeks, the pair have rocked back and forth between being the richest person in the world. To date, Bezos takes the top spot with a net worth of $187 billion while Musk sits at $180 billion, according to the Bloomberg Billionaire Index.

The entrepreneurs also have battled over their space ventures - Musk’s SpaceX and Bezos’ Blue Origin – that have similar goals.

In 2019, Bezos threw shade at Musk when he said that he planned to send people to Mars, telling SpaceNews at the time, “My friends who want to move to Mars, I say, do me a favor and go live on the top of Mount Everest for a year first, and see if you like it, because it’s a garden paradise compared to Mars.”

Musk has also called Bezos a copycat on Twitter when he announced his plans to send satellites to space to provide high-speed internet to remote regions of the world as part of Project Kuiper.

In another tweet from Musk, he said Bezos' plans to create a human settlement on the moon, “makes no sense.”

Shares of Tesla were trading at $711.34 as of premarket hours, up $12.50 or 1.79% while shares of Amazon were trading at $3,165.08, down $29.42 or 0.92% at the same time.

Tesla CEO Elon Musk overtook Bill Gates to become the world's second-richest person after Jeff Bezos
Tesla CEO Elon Musk overtook Bill Gates to become the world's second-richest person after Jeff Bezos AFP / Odd ANDERSEN