AceShowbiz - Katy Perry has been dragged into Kesha's legal spat with hitmaker and producer Dr. Luke after the "Tik Tok" singer accused him of raping her.

In documents, obtained by The Blast, in Luke and Kesha's ongoing defamation case in New York, the music mogul has attacked his former protege for allegations she made about forcing her to take drugs and sexually assaulting her, while dismissing claims she made about raping the Roar singer in an alleged text message sent to Lady Gaga.

"On February 26, 2016 (Kesha) sent a text message to Stefani Germanotta p/k/a/ Lady Gaga which repeated (Kesha's) false claim that (Luke) had raped her," Dr. Luke's complaint reads.

"(Kesha) also fasley asserted that (Luke) had also raped Kathryn Hudson p/k/a/ Katy Perry. Following this text message conversation, and with (Kesha's) encouragement, (Lady Gaga) spread negative messages about (Luke) in the press and on social media."

Fans and those paying attention to the case knew of Kesha's text message to Lady Gaga, but no one knew the contents until now.

Luke claims he lost over $10 million (GBP7.5 million) he would have made for working on Katy Perry's albums, and believes Kesha's allegations damaged his reputation and career.

Meanwhile, Perry has never publicly accused Dr. Luke of any sexual misconduct.

Asked why she walked away from her professional relationship with the hitmaker, Perry has said, "I had to leave the nest".

The new documents obtained by The Blast also suggest Perry has been deposed as part of the lawsuit, but does not go into details about what she said.