Karthik Sivakumar (born 25 May 1977), better known by his stage name Karthi, is an Indian actor who works predominantly in Tamil cinema. He has won three Filmfare Awards South, an Edison Award, a SIIMA Award and a Tamil Nadu State Film Award. Apart from his film career, Karthi has also been involved in social welfare activities, encouraging fans to do likewise through the "Makkal Nala Mandram", a social welfare club that he inaugurated. In 2011, he became a cause ambassador to promote awareness of lysosomal storage diseases. As of 2015, he is the treasurer of the Nadigar Sangam.