Stefani Joanne Angelina Germanotta (/ ˈ s t ɛ f ən i ˌ dʒ ɜːr m ə ˈ n ɒ t ə / STEF-ən-ee JUR-mə-NOT-ə; born March 28, 1986), known professionally as Lady Gaga, is an American singer, songwriter, and actress.She is known for her image reinventions and musical versatility. Gaga began performing as a teenager, singing at open mic nights and acting in school plays.