Who played Cersei Lannister in 'Game of Thrones'?

Who played Sherlock Holmes in 'Sherlock'? Who played Dr. John Watson in 'Sherlock'? In which TV series is Dr. John Watson a main character? In which TV series is Tyrion Lannister a main character? In which TV series is Cersei Lannister a main character? Who played Arya Stark in 'Game of Thrones'? In which TV series is Arya Stark a main character? Who played Sansa Stark in 'Game of Thrones'?