Sophie, Duchess of Edinburgh turns the milestone age of 60 on Jan. 20. Here, fashion insiders, including designers of some of the royal's favorite brands, reveal the secrets of her style evolution.

Sophie, the Duchess of Edinburgh, rang in her 60th birthday by posing for an official portrait in a white Proenza Schouler coat paired with a brown turtleneck and wide-leg bright green pants. The elegant yet modern look paired with a bold splash of color–a welcome departure from the conservative power suits she wore in her early royal days–showed just how far Duchess Sophie’s style has come over the years.

Sophie, the Duchess of Edinburgh is starring in a new portrait for her 60th birthday, and the photographer behind the camera is sharing an unseen snap from the photo session.

In a series of candid photographs by Christina Ebenezer, the Duchess of Edinburgh chose a wardrobe of re-wears that hint at her new era of royal life