Amanda Joy "AJ" Michalka (born April 10, 1991), often credited as AJ, is an American actress, singer-songwriter, and musician. She was a model prior to becoming an actress, and is best known as one-half of the duo 78violet (formerly Aly & AJ) with her sister Aly Michalka. AJ recorded the theme song and accompanying music video for the film Secretariat, entitled "It's Who You Are". She also issued a single and video called "All I've Ever Needed" from her 2013 film Grace Unplugged.
Michalka was born in Torrance, California. She lived and grew up in Seattle, Washington and Southern California with her sister Aly. Her father, Mark, owns a contracting company, and her mother, Carrie, is a musician and performed with JC Band, a Christian band. She has German, English, Irish, and Scottish ancestry. Michalka has been playing the piano since she was four and started playing the guitar in her early teens. She started acting when she was five years old, mostly in church play productions. She was raised as a Christian and continues to practice the faith. Michalka was in a number of musical productions at her school in Milwaukee as a young adult.