This is a single arm, non-randomized, open-label phase 2 study designed to evaluate the tolerability and clinical activity of adding enzalutamide to fulvestrant treatment in women with advanced breast cancer that are ER and/or PR-positive and Her2 normal. In this study 500 mg of Fulvestrant will be given IM on days 1, 15, 28, then every 4 weeks as per standard of care (SOC) and 160mg of Enzalutamide will be, in conjunction with Fulvestrant, PO daily.