Getty Images, Christies, Net-a-Porter,

To celebrate what would have been Yves Saint Laurent's 75th birthday, we decided to take a look back at the incredible designer's stylish muses like Loulou de la Falaise, Betty Catroux, Laetitia Casta and Catherine Deneuve. One of the most important designers of the 20th century, YSL was the head designer at the house of Dior at only 21 years old, leaving to launch his eponymous line a few years later in 1961. Credited with elevating ready-to-wear, reinventing couture and introducing the famous "le smoking" jacket for women, Yves Saint Laurent's legacy continues to be present today.

Take a peek in our gallery below for some of YSL's seriously chic BFFs: