Justin Bieber -- Goes Extremely Blond ... Take That Ellen DeGeneres

Justin Bieber hit the bottle a little too hard -- as in the bottle of hair dye -- and he's now emerged as a platinum blond version of himself.

The Canadian pop star, and super-expensive car enthusiast, debuted his new lighter looking locks over the weekend ... during the ribbon cutting ceremony for a West Coast Customs car shop in Burbank, CA.

Whatever you might think of Justin's new 'do, you can rest assured ... Portia de Rossi probably loves it.