Madonna Louise Ciccone is an American singer, songwriter, record producer, and actress. Commonly referred to as the "Queen of Pop", she is known for her continual reinvention and versatility in music production, songwriting and visual presentation. Madonna's works, which incorporate social, political, sexual, and religious themes, have generated both controversy and critical acclaim. A cultural icon spanning both the 20th and 21st centuries, she has become the subject of various scholarly, literary and artistic works, as well as a mini academic sub-discipline called Madonna studies.