Katy Perry is about to launch her new fragrance, Killer Queen.  Now, she's also the queen of Twitter.

Katy has topped Lady Gaga as the most-followed woman on Twitter.  As of Thursday morning, Katy has just under 39.9 million Twitter followers, compared to Lady Gaga's 39.3 million.  Those numbers also make Katy the second most-followed person on Twitter, period, followed by Lady Gaga in third place.

In fairness, Gaga has been largely absent from social media this year as she recovers from hip surgery and works on her next album, ARTPOP.  That includes changing her Twitter avatar to the generic egg, apparently in preparation for a re-launch of her Twitter presence.

Mind you, both Katy and Gaga take a back seat to Justin Bieber, who currently boasts 42.3 million Twitter beliebers, making him the single most-followed person on Twitter.

Here are the top ten most-followed people on Twitter, according toTwitterCounter.com:

1) Justin Bieber -- 42.3 million followers
2) Katy Perry -- 39.9 million
3) Lady Gaga -- 39.3 million
4) Barack Obama -- 34.5 million
5) Taylor Swift -- 31.3 million
6) YouTube -- 30.9 million
7) Rihanna -- 30.7 million
8) Britney Spears -- 29.7 million
9) Instagram -- 23.4 million
10) Justin Timberlake -- 23.2 million