Justin Bieber Accidentally Gives Away Award

Bieber was in Toronto Sunday for the MuchMusic Video Awards -- and when he left the stage after accepting his trophy for UR Fave Artist ... he was accosted by several fans in the front row.

Bieber pump-faked with the award -- but a girl latched on to it, so Bieber handed it over ... obviously thinking she was an extremely young, extremely loud award show official.

But she wasn't -- and the random girl was later approached by a REAL award official, demanding she return the trophy ... which she did.