Summer Glau

 The first time she appeared on TV was as a guest-star in the 2002 episode of Angel. Director Joss Whedon spotted her and decided to cast her as River Tam on his short-lived TV series Firefly. She also played in the role for the sequel Serenity. Glau had previously tried to audition for the role of a Power Ranger (White Wild Force Ranger Alyssa Enrile) in Power Rangers Wild Force but was defeated by the actress Jessica Rey before meeting Whedon.Glau appeared on the episode "Love Conquers Al" of the TV series Cold Case. Glau had a small part in the movie Sleepover where she played high school senior Shelly. She also appeared in the CSI: Crime Scene Investigation episode "What's Gilbert Grissom Eating? " The second season of The Unit as Crystal Burns (the girl of Jeremy Erhart). Glau was Tess Doerner (a paranoid, psychotic returning character) in the second season of The 4400. From season three, she became a regular character. Glau was also in Mammoth the horror comedy. Glau was cast in the ABC Family TV movie The Initiation of Sarah.In Terminator: The Sarah Connor Chronicles, a series that debuted January 13, 2008, Glau was the character Cameron Phillips, a Terminator infiltration unit sent back to protect John Connor and Sarah Connor from Skynet. The series' seventh episode, "The Demon Hand" included scenes in which Glau (as Cameron) dances ballet. Glau also played Allison Young (Cameron’s human doppelganger ) during episodes from the second season, "Allison of Palmdale" and"Born to Run". Glau also starred as herself on a CBS episode in 2009 of The Big Bang Theory's situation comedy.