Musk wrote simply “#bitcoin” in his biography on the social media site. The world’s biggest cryptocurrency was up 10.2% at $36,901 as of 1005 GMT.
The billionaire entrepreneur, followed by 43.8 million users on Twitter, has a record of making market-moving comments on the site.
GameStop Corp, which has been at the centre of retail trading frenzy, surged 50% on Tuesday after Musk tweeted “Gamestonk!!”, along with a link to the Reddit Wallstreetbets stock trading discussion group. There, supporters affectionately refer to him as “Papa Musk.”
“Stonks” is a tongue-in-cheek term for stocks widely used on social media.
Bitcoin jumped over 300% last year, as bigger U.S. investors and corporations sought exposure to the cryptocurrency. It touched an all-time high of $42,000 last month.
In December, Musk asked about the possibility of converting “large transactions” of Tesla’s balance sheet into bitcoin, in a Twitter exchange with a well-known advocate for the digital currency.
“That would be a very big deal,” said Christopher Bendiksen of digital asset manager CoinShares on Friday.
Traders also cited positive comments on bitcoin by hedge fund manager Ray Dalio as supporting sentiment.
The Bridgewater Associates founder wrote on Thursday that the cryptocurrency was “one hell of an invention,” adding that he viewed it as a “gold-like alternative asset.”
Smaller cryptocurrencies including ethereum and XRP that tend to move in tandem with bitcoin also jumped, as much as 5% and 8% respectively.