Sir John Barnett (born July 1, 1982), known professionally as Sir John, is a global make-up artist, activist, influencer, and executive. He is best known for being a creative collaborator and make-up artist of Beyoncé. Among those he has done make-up work for include Naomi Campbell, Serena Williams, Chrissy Teigen, Priyanka Chopra, Margot Robbie, Zendaya, Naomi Osaka, Mary J Blige, Iman, Celine Dion, Viola Davis, Erykah Badu, Joan Smalls, and Kat Graham. Sir John is a creative director for L'Oreal Paris USA and the Chief creative officer of CTZN Cosmetics.