The fashion model and Patriots star married in 2009 and are also the parents of a 2-year-old son named Benjamin.
Benjamin's little sister was born Wednesday night, the Globe said Friday.
No other details regarding the child's birth were immediately available.
Brady also has a 5-year-old son, John, with his ex-girlfriend, actress Bridget Moynahan.
Celebrity Families of 2014 [PHOTOS]