Zedd has hit back at Matthew Koma after he called him "toxic and self-serving".
The 32-year-old songwriter - who is engaged to Hilary Duff - launched a scathing attack on the EDM producer last week for taking the credit for all of the lyrics on their hit songs 'Clarity' and 'Spectrum' released in 2012.
And this weekend, Zedd fired back with a lengthy response of his own, in which he said he felt "hurt" by Matthew's comments.
In a response posted on Twitter, Zedd wrote: "I just wanted to let my fans know my side of the story. I have given Matt songwriting credit for every topline he has written.
"What hurts the most is that Matt feels underappreciated and treated unfairly while I have countless times mentioned him (or) his name, while we've done promo together, performed our songs live together and I thought I was being supportive.
"Anywhere you look, you will see Matt credited for his work. I wish he would have just let me know in person what he was feeling. I never want anyone I work with to be unhappy. I treat everyone I work with love and respect and it hurts me to see someone feeling differently after seven years. (sic)"
The 29-year-old producer then said he hopes he and Matthew can patch up their friendship one day.
He added: What I told Matt doesn't change - I am incredibly proud of our work together and I continue to wish him nothing but the best. Hopefully one day we can sit down together again as friends."
In Matthew's original comments, he claimed he no longer had any "good feelings" toward the work he'd done with Zedd.
In lengthy iPhone notes shared on his Twitter page, Koma wrote: "In response to years of: 'What happened with you & Zedd.' I want to finally be transparent about this.
"it's a really sad truth because I'm extremely proud of the work he and I did together. Unfortunately my good feelings toward those songs have all but disappeared as they were experienced alongside someone so toxic and self serving that it occupied the space where any happiness could exist.
"It's not that dramatic of a story and it comes down to something simple.
"S***** people suck and when they're successful, people are afraid to blow the whistle ... (sic)"