Before heading inside, the 18-year-old singer was all smiles as he posed in a Dolce&Gabbana shirt, Marc by Marc Jacobs pants, and Supra shoes.
“Just gonna have fun with it tonight,” tweeted Justin. “I already won = my Beliebers, but regardless when it comes time to perform…we are going in!”
Earlier in the day, he tweeted a special message to his girlfriend, saying, “Happy birthday @SelenaGomez!!! everyone show love!!”