YSL Beauty has tapped Austin Butler as global ambassador of its new fragrance Myslf, its first   “I was honored to be asked to join the YSL Beauty family,” said Butler. “Over the last few years, I’ve spoken with people who knew M. Saint Laurent. He broke through labels. He was a rebel, and I love that about him. I feel privileged to be a part of the heritage he set in motion.”   The American rising star has already collaborated with some of the most prestigious directors —Quentin...