The 23-year-old singer made an impromptu performance last night at Power105.1's DJ ProStyle Birthday Bash Concert at the Hammerstein Ballroom in New York City.
Rihanna's on-again, off-again boyfriend hit the stage shirtless wearing only sagging tan pants that showed off his black Polo Ralph Lauren underwear. Brown also couldn't help tugging at his trousers in front of the crowd.
"I love NYC," he tweeted yesterday. "The line Is around the block. Lets turn up tonight! #nodrama #staypositive #lovemylife."
Brown followed up postperformance with, "I love all my fans who came out tonight. Wasn't supposed to perform but I couldn't resist. I l0ve y'all!"
Ciara, Fat Joe, Wale and Fabolous also performed during the concert event.