The Tik Tok singer and the producer have been engaged in a legal battle since 2014, after she accused him of verbally, sexually, and physically abusing her while she was signed to his Kemosabe Records label, a subsidiary of Sony Music. Luke has repeatedly denied the allegations.
Kesha lost her bid to cut ties with Kemosabe last year (16), but now her lawyer has filed new documents in a New York court, urging the judge to reconsider the ruling and allow the pop star to "be free from her abuser and rebuild her physical, emotional, and mental health".
To strengthen their argument, her legal representatives have submitted a collection of emails allegedly exchanged between Luke and Kesha's manager, Monica Cornia, which appear to back up claims of his reported verbal abuse.
In one message from June, 2012, obtained by the New York Post, Luke defended comments he had allegedly made to Kesha after he caught her breaking her diet.
"Nobody was calling anybody out," he told Cornia. "We were having a discussion on how she can be more disciplined with her diet. there have been many times we have all witnessed her breaking her diet plan. this perticular (sic) time - it happened to be diet coke and turkey while on an all juice fast."
Cornia tried to convince Luke to be more supportive of the singer, insisting she is "a human and not a machine".
Another email details Luke's concerns that Kesha's figure was putting potential collaborators off the idea of working with the singer.
"A list songwriters and producers are reluctant to give Kesha their songs because of her weight," he reportedly wrote.
Kesha has since revealed she struggled with eating disorders and even contemplated suicide at the height of her personal issues, which she blamed on her toxic working relationship with the producer, real name Lukasz Gottwald.
The email leaks emerge days after Luke launched a counterclaim against Kesha, claiming he is owed $1.3 million (£1 million) in unpaid royalties.
The two parties are due to take part in a phone conference with the judge next week (begs20Feb17) to discuss the latest accusations.