Perry now has just over 46.5 million followers on Twitter to Bieber's 46.49 million, ending his nine-month reign as the most-followed user on the service. The buzz around her new album Prism is the main reason for Perry's current social surge.
Musicians remain some of the most popular users on Twitter, accounting for four of the five most-followed accounts. Lady Gaga's 40.4 million followers puts her third, having spent three years as the biggest Twitter star before being overtaken by Bieber in January this year.
Taylor Swift's 36.25 million followers puts her fifth on the chart, with only US president Barack Obama breaking up the top five with his 39.27 million followers.
Perry recently talked about her social media strategy, telling USA Today that "I've learned how to ride social media ... I feel like I've learned how to tame that social media dragon" before giving fellow stars advice on how to follow suit.
"When you decide to have a glass of wine, put the phone down. Don't drink and tweet. Don't be self-indulgent. Don't use it just to promote yourself. That's boring."
