With her career on the upswing, Britney Spears now has one more thing to celebrate: on Friday, the pop star became the latest celebrity to reach the eight-figure follower mark on Twitter.

She is the sixth person, fourth woman and third female musical artist to become a member of Twitter’s so-called “10 million club,” whose membership already boasts stars such as Lady Gaga, Justin Bieber, President Barack Obama, Katy Perry and Kim Kardashian.

So who’ll be the next inductee? Probably ‘Hips Don’t Lie’ singer Shakira, who’s currently sitting at 9.1 million followers.

Meanwhile, the bad news keeps coming for Ashton Kutcher. Although the actor — who’s currently embroiled in a cheating scandal that may cost him his marriage to wife Demi Moore — was the first Twitter user to rack up a million followers, it’s projected that he’ll soon fall off the list of the top ten most-followed people on the microblogging service.

[MediaBistro]