If you doubted the staying power of the pink hair trend, you shouldn't have. Because it doesn't seem to be going anyway. Even though Heidi Klum said the look wasn't "age-appropriate" for her, there doesn't seem to be a shortage of stars adopting the on-trend hair hue. The latest being Nicole Richie, who tweeted this snap overnight. Not one to let her husband have all the hair dyeing fun — last week it was green, black and blue for Joel Madden, this week tiger stripes — Nicole is showing off hot pink mid-lengths to ends joining the ranks of Coco Rocha and Lauren Conrad who have sported a similar shade this year. What do you think of Nicole's latest look?