Academy Award-winning actor Philip Seymour Hoffman was found dead in his New York City apartment this afternoon. The New York Police Department is investigating with the Office of the Chief Medical Examiner to determine exact cause of death, but some headlines are citing a drug overdose. The actor has struggled with substance abuse in the past, but remained clean for over 20 years — until 2013 when he entered rehab for a heroin addiction and prescription pills. An accomplished theater veteran, Hoffman was a frequent collaborator of director Paul Thomas Anderson’s, appearing in five of his films, including Boogie Nights, Magnolia, and most recently, The Master. The celebrated actor leaves behind three children and his wife, costume designer Mimi O’Donnell.