Speaking on Australia's "The Kyle and Jackie O Show" on Friday, May 17, the 37-year-old accused his fellow judge of being "awful" to him during the filming of the show, while he previously told Australia's Stellar magazine that the star wasn't "invested" enough in her role.
Shortly after the singer-songwriter made the comments, the rapper took to Twitter to clap back at Guy in a string of since-deleted tweets, writing: "I want to talk about how Guy Sebastian is a complete liar, let's get into it!"
"1. How can you be late for a show that was filmed on LIVE television firstly... I'd love to know, Guy!" she began. "2. If you dislike me so much, what's up with all the interviews with you saying you expected to dislike me but that I'm really sweet and lovely?"
"3. Remember when half way into the season you started having 'beef' with me that was entirely fabricated by the show and you told me you were sorry but you wanted to go along with 'upstairs' requests to create 'drama' so you could make sure you remained a judge for next season?... I love that you're STILL using me to drum up attention for a show your on, what's new (sic)?"
The "Black Widow" star went on to slam her fellow Australian, who is now a judge on "The Voice Australia", for his "deep rooted hatred of the 'type' of woman I am", and claimed he was intimidated by her outspoken nature.
Wrapping up the tirade, Iggy took a swipe at the "Who's That Girl" star's fashion sense and bank balance while wishing him the "best of luck".
"Anyway, best of luck to you and your fedoras! Everyone, please watch Guy Sebastian. He's on 'The Voice Australia' and he really, really desperately needs the ratings to feed his children," she concluded.