He's shot countless covers for Vogue and Vanity Fair, photographed everyone from Margaret Thatcher and Anna Wintour to Gwyneth Paltrow and Lady Gaga and, more recently, snapped Prince William and Catherine Middleton's engagement photos. But even Mario Testino now one of the world's most well-known and respected fashion photographers had to start somewhere. After moving to London from his native Peru in 1976, Testino shot models' portfolios for a pittance and fought to get his work in front of editors. By the time he had settled in London permanently in the 1980s, he had found modest success as a fashion photographer. But the break that truly cemented his fame was bigger than most. In 1995, Madonna saw his photographs in a magazine and was so taken by them that she requested he shoot her upcoming campaign for Gianni Versace. That was all it took. In the nearly 20 years since, Testino has published nine photo books and contributed to the image development of leading fashion houses including Burberry, Michael Kors, Dolce & Gabbana, Valentino, Estee Lauder, Miu Miu, Hugo Boss, Calvin Klein and Salvatore Ferragamo. Along with Tom Ford, he helped revive the house of Gucci in the 1990s and helped discover Kate Moss and Giselle, two of the most famous (and bankable) models to ever walk the runway. Beyond fashion, he was a favorite of Princess Diana; Testino photographed her for Vanity Fair just months before her death in 1997 and continued to capture her sons at major milestones through the years.