Gwyneth Paltrow is opening up and giving some rare insight into her life as a stepmom to her husband Brad Falchuk's daughter, Izzy. "Happy Birthday my snizzle," Paltrow, 52, wrote via her Instagram Stories on Saturday, September 6, in honor of her stepdaughter's 21st birthday. "You have taught me so much about love," the actress and entrepreneur continued. "I am lucky to be your stepmom." Paltrow became stepmom to Izzy and her brother, Brody Falchuk, in September 2018, when she married their dad, Brad.