Justin Bieber's Alter Ego 'Derek' Tops Twitter Trends (VIDEO)

Don't worry there isn't another Bieber, it's only Justin.

But if you were wondering why "Derek Bieber" has been trending on Twitter since yesterday, it's because the teen heartthrob was just having a little fun with an annoying paparazzo.

TMZ caught up with Bieber while he was walking around L.A. and asked the pop star about being called a "brat" by American Airlines. Bieber -- who has definitely had some good media training -- refused to play the cameraman's games, replying:

"I've never heard that rumor, ever... I don't think you should believe everything you hear. People say I'm dead today; that's the rumor."

It's amusing to watch the 17-year-old take the unrelenting cameras in his face with stride, then joking he was actually heading to his own funeral.

And when asked how he responds to hearing things like being called a brat, Bieber sarcastically replied:

"I'm famous? I'm a celebrity? I didn't even realize. My name is Derek, I don't know what you guys are talking about. I'm just a lookalike. I don't know why you guys are following me around with cameras and stuff."

Well played, Bieber. Guess we can add Derek to the growing list of Bieber's aliases that include: Jason McCan, Jason Deeps, Shawty Mane, and Purple Ninja.