Justin Bieber hammed it up with a toy robot at the consumer electronics show in Las Vegas.
The giveaway? You can clearly see the Levi's label on the pocket.
A Louis Vuitton spokesman said: "The jacket Justin Bieber is wearing is a cheap knockoff of the Louis Vuitton brand. Anything unauthentic, worn by a famous individual ... is seriously frowned upon."
And it's not the first time. Bieber and his buddy Jaden Smith once wore jackets that also bear the Louis Vuitton logo and they're just as fake as the one causing a headache for Bieber.
Louis Vuitton also filed a lawsuit against Warner Brothers last month over the knock-off bag carried by Zach Galifianakis in Hangover 2.
So Bieber, the lesson from Louis seems to be: Don't mess with the best!