Makeup artist Daniel Martin (whose A-list clients include Meghan Markle, Elisabeth Moss, and Jessica Alba) swears by Dior Forever Matte Foundation (£37) for his clients with oily skin. "This formula gives a matte, but not a flat finish," he said. "It also doesn't oxidise over time — even when in contact with the natural oils in your skin — so it stays true to tone after hours of wear."