Salma Hayek did it. So did Angelina Jolie, Jessica Alba, Christina Aguilera, Rachel Weisz, Gwen Stefani, Liv Tyler, Faith Hill, Elle Macpherson, and Kate Beckinsale. They were all nursing moms who breastfed and/or expressed milk for their babies. Whether you're returning to work, relieving engorgement, or pumping milk so you can have a night out, at some point all nursing mothers need to learn the art of expression.