Now, Dr. Luke (real name Lukasz Gottwald) is firing back with his own defamation lawsuit against the pop star, claiming she (along with her mother, Pebe) is extorting him to get out of her long-standing contract with the producer.

"As part of the effort to get out of the Gottwald Recording Agreement," the claim read (via Billboard), "Kesha and Pebe have also orchestrated a campaign of publishing false and shocking accusations against Gottwald to extort Plaintiffs into letting Kesha out of the Gottwald Recording Agreement."

Dr. Luke has worked with a number of high profile stars, including Katy Perry, Kelly Clarkson, and recently, French dance-pop outfit Yelle, but his relationship with Kesha differs from these in that he worked with her from when she was an unknown, the time from which her allegations stem.