ROBYN BECK/AFP via Getty Billie ... favorite hair colors over the years. "Well, I really like to romanticize two specific periods in my life: the green roots and the red roots," Eilish said.

Billie Eilish just shut down the haters who have a problem with her signature neon green hair. The "Bad Guy" singer-songwriter, 19, who's become known for rocking the statement-making lime green ...