Bill Gates joined Twitter yesterday, and immediately signed up to follow Ashton Kutcher, High School Musical star Ashley Tidsdale and American Idol presenter Ryan Seacrest.
The Microsoft founder already has more than 160,000 followers - a number that is increasing quickly. He said, "I've got a lot to learn about Twitter but look forward to sharing more."
Gates is likely to use the account to publicise and talk about the work of the Bill and Melinda Gates Foundation, which works to alleviate hunger, poverty and poor health in developing countries.
Gates stepped down as CEO of Microsoft in 2000 but remains a non-executive chairman at the company.
He is the latest of a number of high-profile technology figures to sign up to Twitter. Google's Marissa Mayer has been using it since July last year, and internet inventor Tim Berners-Lee signed up recently.