Kaley Christine Cuoco (born November 30, 1985) is an American television actress best known for her role as Bridget Hennessy on the ABC sitcom 8 Simple Rules. Although she played the oldest child of the family, she is, in reality, six years younger than her co-star, Amy Davidson, who played the middle child. She parodied herself on one episode of 8 Simple Rules in a cold opening sequence. She is also known for her role on the WB hit series Charmed as Billie Jenkins starring alongside Holly Marie Combs, Alyssa Milano, and Rose McGowan. She can be currently seen on The Big Bang Theory with Johnny Galecki and Jim Parsons.