Kristen Stewart celebrates her 20th birthday today and whilst PopSugar UK is testing your knowledge of the actress, I thought I'd see how well you know her style. She has made many red carpet appearances recently either due to promoting one of her films, or as she attends awards season. Whilst her red carpet style may not be that conventional, she's worn a range of key designer pieces and she has certainly got people talking. Take my quiz and answer, who designed her dress? Happy Birthday Kristen!