SPJ started this trend in season 6 of Sex and the City.
beautiful ombre hair
Art brunette brunettes
all hair color combo's can have this look. the main thing is the placement of the light and dark, which depend on face shape. Also make sure color tones go well with skin.
beautiful ombre, beautiful selma hayek! People yes this trend came out 3-4 years ago, but as you can see it is still going. Selma at Golden Globes 2012