Elon Musk on Tuesday set a deadline for purging legacy blue check-marks from Twitter accounts verified under the company's previous regime.

"Final date for removing legacy Blue checks is 4/20," tweeted billionaire owner of Twitter, Musk.

This means that if you have a legacy verified account on Twitter with a blue mark, you will have to pay now to keep the checkmark.

The only accounts that will keep their blue checkmarks are those subscribed to Twitter Blue.

Twitter Blue is priced differently for every region and based on how you sign up. In the US, it costs USD 11 a month or USD 114.99 a year for iOS or Android users and USD 8 a month or USD 84 a year for web users.

Twitter previously announced that starting April 1, it would begin removing the blue check-mark badges from legacy verified accounts -- those which the company had previously deemed to be notable and/or authentic -- unless users have signed up for the Twitter Blue subscription service.

On April 2, Twitter changed the language in the description of verified users to read, "This account is verified because it's subscribed to Twitter Blue or is a legacy verified account" -- which means you can't tell who is paying for a blue check-mark and who isn't.

Meanwhile, some celebs refused to pay for verification. LeBron James, the NBA star and entertainment producer, had tweeted on March 31, that his blue checkmark likely would be disappearing because he wouldn't pay for verification.

"Welp guess my blue [?] will be gone soon cause if you know me I ain't paying the 5. [?]," tweeted James, however @KingJames remains verified.

Musk is making the switch to paid verification in order to generate much-needed revenue for Twitter.

Stephen King rejected the idea of paying for a blue checkmark ("F... that," King tweeted), Musk responded, "We need to pay the bills somehow!"

Meanwhile, Twitter has launched a program for businesses and organizations to charge USD 1,000 per month for verification badges (gold for brands, companies and nonprofits; grey for governments).

Twitter first introduced verified accounts in 2009 to help users identify that celebrities, politicians, companies and brands, news organizations and other accounts "of public interest" were genuine and not impostors or parody accounts. The company didn't previously charge for verification.