Blue Origins CEO Jeff Bezos took time on Monday to offer his fellow billionaire Elon Musk some advice on how to repurpose Twitter headquarters; fuse the office with a homeless shelter.

Bezos, who rarely posts on Twitter, made the suggestion on Sunday in response to a poll by the Tesla CEO where he questioned how the social media company’s headquarters should be renovated.

"Convert Twitter SF HQ to homeless shelter since no one shows up anyway," Musk posted Saturday on Twitter.

In his post, Bezos included a link to an article that detailed how Amazon did something similar with its Seattle-based headquarters.

“Worked out great and makes it easy for employees who want to volunteer,” Bezos posted.

Musk, who later deleted his tweet, responded to Bezos: “Great idea.”

The interaction between the world’s two richest men comes after Musk was slated to join Twitter’s board of directors after becoming a majority shareholder in the social network. However, it was announced on Monday that Musk would no longer be joining the board.

In October 2017, Bezos was named the world's richest man, a title he held for over three years before being dethroned by Musk in January 2021. According to Forbes' billionaire index, Musk’s net worth is currently $264.4 billion compared to Bezos’ $177.5 billion.

There has been an unofficial rivalry of sorts between Bezos and Musk as well as the companies that they lead.

Bezos’ Blue Origin unsuccessfully sued NASA in August 2021 after losing out on a lucrative federal contract to Musk’s SpaceX during the bidding process. A federal judge ruled against Blue Origin in November 2021, leaving SpaceX victorious and Musk gloating online about it.

But Bezos has managed to secure a win over Musk in the unofficial space race between the two. Last July, Bezos flew onboard a Blue Origin spacecraft for an 11-minute voyage in the first commercial flight to outer space.

Musk, who frequently muses about space travel, soon caught up when SpaceX launched four private passenger planes into space last September and they spent three days in outer space.