Twitter on Thursday began removing legacy blue checkmarks from user profiles, with famous people including pop icon Beyonce and Pope Francis losing their verified statuses.
Some personalities such as basketball star LeBron James and author Stephen King still had their checkmarks.
"The Shining" author King, who has previously called Musk a terrible fit for Twitter, tweeted: "My Twitter account says I've subscribed to Twitter Blue. I haven't. My Twitter account says I've given a phone number. I haven't."
Musk tweeted back to him: "You're welcome namaste," with a hands folded emoji.
The Verge reported that James, who has previously said he would not pay for verification, had not paid to keep the check mark.
Musk tweeted separately: "I'm paying for a few personally." and later tweeted "Just Shatner, LeBron and King," referring to Star Trek actor William Shatner, who had last month complained about being forced to pay to keep his blue checkmark.
Among those losing their badges were former US president Donald Trump, Microsoft Corp cofounder Bill Gates and reality TV star Kim Kardashian.
Under Musk's ownership, Twitter has changed how it hands out the coveted blue checkmarks that were earlier given to noted individuals, journalists, executives, politicians and establishments after verifying their identities. They served as a mark of authenticity.
Musk said in November that Twitter will begin charging US$8 per month for the badge in an effort to launch new revenue streams beyond advertising.
The company later offered check-marks in other colours - gold for businesses and a gray for government and multilateral organisations and officials.
It has also started displaying labels like "state-affiliated" and "automated by" against accounts to show when an account is linked to a government or is a bot.
US non-profit National Public Radio stopped posting content on its 52 official Twitter feeds after Twitter labeled it "state-affiliated media" and later "government-funded media".
Public broadcaster Canadian Broadcasting Corporation also paused its activities on Twitter and sparred with Musk over Twitter's definition of government-funded.