Gaga has publicly stood by Kesha's side amid the drama, but Perry's involvement comes as a surprise.
Dr. Luke produced several of Perry's hit songs — including "Roar," "California Gurls," and "I Kissed a Girl" — but Perry's role in Kesha's sexual assault case against Dr. Luke remains a mystery.
More information will be released as the case continues.
Both Kesha and Dr. Luke's legal teams argued their points at a conference on December 26; however, the battle is far from over. In addition to Kesha's sexual assault and battery claims against Dr. Luke and the producer's countersuit, Kesha also sought a preliminary injunction that would allow her to release music outside of Dr. Luke's authority. However, a judge denied the request in February, prompting the viral #FreeKesha hashtag.