Priya Koothrappali is Raj 's younger sister. She first appeared in " The Irish Pub Formulation " and serves as the unintentional main antagonist of season 4 in that Penny regards Priya as Leonard 's most viable alternative girlfriend. Though she often looks annoyed or exasperated, she can be quite funny.
The American television sitcom The Big Bang Theory , created and executive produced by Chuck Lorre and Bill Prady , premiered on CBS on September 24, 2007.
Aarti Majumdar (born March 3, 1978), better known by her stage name Aarti Mann , is an actress of Indian ancestry. She has starred in several television programs, including a part in the sci-fi drama Heroes . She is best known for playing the role of Priya Koothrappali in The Big Bang Theory .