Elon Musk and Jack Dorsey's relationship is a rare example of tech CEOs supporting one another. Take a look at the evolution of their crypto bromance.

The Twitter CEO said Musk's account on the social platform was one of his favorites.

"He's constantly on Twitter, constantly talking about what [Tesla is] doing — and how he's feeling about it as well," Dorsey said at a trade show in 2016. "He's very open and using it to correct press and if people aren't focused on the right things. I think he's a really good model of how to use it well."

Dorsey asked Musk for "direct feedback" in a video call in front of thousands of Twitter employees.

The Tesla CEO said it would be helpful to tell fake and real users apart.

"Is this a real person, or is this a bot net, or a sort of troll army, or something like that?" Musk said.

An activist hedge fund that had amassed about a 5% stake in Twitter pushed an initiative to drive Dorsey out of his role as CEO. The hedge fund, Elliot Management, reasoned that since Dorsey led two companies, Twitter and Square, he wasn't focused enough on the former.

Musk — who also helms two companies — tweeted, "Just want say that I support @Jack as Twitter CEO. He has a "good" heart, using the heart emoji.

Hackers staged a coordinated attack on dozens of celebrity accounts last summer, and Musk's was one of them. He told The New York Times that he personally called Dorsey after realizing he was hacked.

"Within a few minutes of the post coming up, I immediately got texts from a bunch of people I know, then I immediately called Jack so probably within less than five minutes my account was locked," Musk told the Times.

Dorsey especially has thrown his support behind the digital currency, which has seen booming popularity and growth recently, although it's grappling with a sizable dip at the moment.

The Twitter CEO has simply "#bitcoin" in his account bio and said at Miami's bitcoin bonanza earlier this month that "Bitcoin changes absolutely everything. I don't think there's anything more important in my lifetime to work on."

His payment processing company Square held 8,027 bitcoins in mid-May.

And he said in a series of tweets in early June that Square was toying with building out a hardware wallet for bitcoin.

Musk has said he strongly believes in crypto, and Tesla said at one point it would accept vehicle purchases in the form of bitcoin. The CEO also included the #bitcoin hashtag in his Twitter bio at one point.

But in mid-May, Musk announced the company was suspending bitcoin payments over concerns around the use of fossil fuels for bitcoin mining and transactions. He said Tesla would start accepting it when at least half of bitcoin mining is powered by clean energy.

Musk has kicked off market rallies for the tweets he posts about cryptocurrencies, much to the anger of regulators and investors.

The most recent was when he tweeted "my Shiba Inu will be named Floki," a reference to the Shiba Inu that represents dogecoin. The altcoin shot up 16% just minutes after Musk published his tweet.

Dorsey posted about an upcoming bitcoin event called "The B Word" on Twitter, and after Musk responded to it, the Twitter CEO invited him to attend for a conversation.

Musk responded, "For the Bitcurious? Very well then, let's do it," and added a wink face emoji. Dorsey said he would set it up.

The conference will kick off on July 21, though it's unclear if it will be virtual or in-person.

But either way, it'll be what appears to be the first public appearance starring the two friendly executives.