Justin Bieber: Surprise Concert!

Justin Bieber serenades fans after making an appearance on The Tonight Show with Jay Leno on Wednesday (June 27) in Burbank, Calif.

The 18-year-old heartthrob showed his Beliebers some love by singing them his hit single, “Boyfriend“.

PHOTOS: Check out the latest pics of Justin Bieber

“From a town of 30,000 – on my 18th bday we hit 18 MILLION…and now 4 months later we are at 24 MILLION BELIEBERS!!!” Justin tweeted. “#TEAMBIEBER GOES HARD!”

Check out a clip below of Justin chatting with host Jay Leno!

10+ pictures inside of Justin Bieber singing to his fans…