• Mike Tyson
The former boxer has lent his name to a line of Bitcoin cash machines. The Mike Tyson Bitcoin ATM will let people purchase Bitcoin using their mobile devices, according to Bitcoin Direct, which operates the machines. The company says it will turn on the first machine in Las Vegas on Sept. 24. "Mike Tyson's fastest knockout in the ring was 30 seconds," Bitcoin Direct writes in an ad. "The Mike Tyson Bitcoin ATM can turn your cash into bitcoin in under 20 seconds."
The rapper asked fans last year to participate in an online contest called the Nas Rap Test. Coinbase, a Bitcoin startup that claims Nas as an investor, promised to give 100 winners Bitcoin for their hip-hop knowledge.
• Richard Branson
In May, the Virgin Group billionaire co-founder held the four-day Block Chain Summit on his private island in the British Virgin Islands. Attendees who traveled to Necker Island for the conference not only discussed Bitcoin but also kite-surfed, played pool, and "shaped serendipity," as Branson explained in a blog post.
• Ashton Kutcher
The actor and longtime startup investor, who's a backer of BitPay, responded to a question on Quora suggesting that people should put their money into Bitcoin. In 2013, Kutcher promoted Bitcoin at another event, TechCrunch Disrupt.
• Richard Sherman
Last year, the Seattle Seahawks cornerback announced on his Facebook page that fans could buy merchandise from his online store using Bitcoin. BitPay, which the store uses to process payments, also promoted the news on its Twitter account. The outspoken athlete called it "the currency of the future," which is one celebrity endorsement the Bitcoin faithful might actually agree with.