Karthik Sivakumar (born 25 May 1977), best known by his stage name Karthi is an award-winning Tamil film actor. He is the younger son of veteran actor Sivakumar and brother of Surya Sivakumar. He is best known for his role in his debut film Paruthiveeran in 2007, for which he received the Filmfare Best Tamil Male Debut Award and Filmfare Best Actor Award.
http://en.wikipedia.org/wiki/Karthik_Sivakumar