Check out Justin Bieber singing a mash-up of Justin Timberlake’s Cry Me a River & Usher’s You Got it Bad!

Amazing!  Adorable!  Fantastic!   What do you guys think!?  Do you have BIEBER FEVER!?!

Justin Timberlake performed in Las Vegas this weekend, and surprised the audience with a little “Use Somebody/Cry Me a River” mashup.  (Does anyone else think that Glee has officially brought back the amazingness that are mashups??)

Check out JT mashin it up beautifully below: