Twitter IPO

On eve of expected IPO, Twitter has new top bird

Andrew Harrer | Bloomberg | Getty Images

Say it ain't so, Beliebers.

Just days before Twitter's expected IPO on the New York Stock Exchange, singer Katy Perry (@KatyPerry) has become the service's most popular user, taking the title away from fellow artist Justin Bieber (@JustinBieber).

With 46.48 million followers, Perry edged in front of Bieber's 46.47 million Sunday afternoon, claiming the top spot in terms of fans on the seven-year-old platform. (Bieber sat in first place for nine months after bumping Lady GaGa out of the ranking which she dwelled in comfortably for two years.)

(Read more: Twitter's mysterious outside shareholder)

While some in the social media space will advise you not to equate the amount of followers a user has with a level of popularity, "Twitter's most followed user" is a ranking held in high esteem. Just four years ago, actor Ashton Kutcher made headlines when he beat out CNN to being the first Twitter user with one million followers.

The Week Ahead: Twitter goes public

Those wary of the follower metric will quicker glance at a user's "Klout score," – a number from 1 to 100 that signifies how much engagement a particular account is receiving.

Although Perry may have more followers than Bieber, Klout shows that both singers have a score of 95, a respectable number that suggests tremendous influence. Furthermore, Bieber's tweets generally receive more retweets and favorites than Perry's, based on a review by CNBC.

(Read more: Why Twitter's IPO should be more like Facebook's)

The question to ask though is how many of the combined 92 million accounts are real?

StatusPeople, a tool that determines how many of a Twitter user's followers are fake, says 41% of Bieber's followers are not legitimate, while Perry has a 'Faker Score' of 52%.

Fans of Bieber were quick to point out this statistic when Perry was crowned on Sunday. "Justin's followers are real unlike Katy Perry's," Twitter user @PurpleBieber wrote.

Another user named @IgnantBieber joked, "Katy Perry could make a breakfast menu with all those egg followers."

Seven of the ten most followed accounts belong to artists in the music industry; the three others are @Instagram, @YouTube and President @BarackObama.

— By CNBC's Eli Langer. Follow him on Twitter @EliLanger