Her ten millionth follower arrived around midnight on May 15th, and Gaga celebrated with - what else? - a tweet and a picture of herself:

Gaga had previously been behind Justin Beiber in the Twitter popularity stakes; he had been the first Twitter user to reach 9,000,000 followers last month, with Gaga close on his tail. I can't explain how much I hope that he reacted to news of Gaga's social media milestone by twirling an imaginary moustache and muttering "You win this round, Gaga... But just wait to see who gets eleven million followers first!" before laughing maniacally.
Source: techland.time.com