Billionaire businessman Elon Musk will join Twitter's board of directors, an announcement that came just hours after news broke that the Tesla and SpaceX CEO became the social media company's largest shareholder.

"I'm excited to share that we're appointing @elonmusk to our board!" Twitter CEO Parag Agrawal tweeted Tuesday morning.

"He's both a passionate believer and intense critic of the service which is exactly what we need on @Twitter, and in the boardroom, to make us stronger in the long-term. Welcome Elon!" Agrawal added.

One day earlier, after it became public that Musk had taken a 9% stake in the company, he asked Twitter users if they wanted what a vocal group of them have been seeking for years: the ability to edit their tweets.

"Do you want an edit button?" Musk asked in a poll.

The answers, cheekily, were "yse" or "on."

"The consequences of this poll will be important," Agrawal said in response, an apparent reference to one of Musk's tweets from last month. "Please vote carefully."

Twitter said Tuesday afternoon that it has been working on an "edit feature since last year" and "didn't get the idea from a poll."

The social media site allows users to post 280-character tweets, but tweets cannot be edited once they're sent — only deleted.

Musk has become a vocal critic of Twitter's limits on what users can say, suggesting that they run counter to free speech.