Eminem. Picture: AP

Eminem and Machine Gun Kelly's diss tracks towards each other were produced by the same person, it has emerged.

The rappers have been locked in a feud ever since the latter hit out at the 'Bad Things' hitmaker on the track 'Not Alike' on his surprise LP 'Kamikaze' last month.

Kelly released a response in the form of 'Rap Devil', which features the line, "Mad about somethin' I said in 2012/

Took you six years and a surprise album just to come with a diss/Homie we get it, we know that you're the greatest rapper alive", and now it has emerged that both tracks featured the handy work of studio wizard Ronny J - whose credits include rappers Lil Pump and the late XXXTentacion.

Kelly took the feud to another level when he poked fun at Eminem's age during his gig in Orlando over the weekend. 

The 28-year-old star couldn't resist mentioning his long-time enemy during his concert at the Amway Center in Florida on Sunday. 

According to TMZ.com, MGK - whose real name is Richard Colson Baker - kicked off his set by shouting "F**k Marshall Mathers," before he added: "The real Slim Shady can't stand up."

Eminem admitted he first dissed MGK because he accused him of hindering his career.

The 'River' rapper explained that he released 'Not Alike', which includes the line: "Now you wanna come and f**k with me, huh? / This little c**k-sucker, he must be feeling himself", after his rival rapped about banning him from his radio station 'Shade 45'.

However, he insisted that he's not interested in wrecking MGK's because there are "better" rappers out there and his name doesn't even pop up in the list.

Eminem said recently: "The reason that I dissed him is because he got on - first he said, 'I'm the greatest rapper alive since my favourite rapper banned me from 'Shade 45,' or whatever he said, right? Like I'm trying to hinder his career. I don't give a f**k about your career. You think I actually f***in' think about you? You know how many f***in' rappers that are better than you? You're not even in the f***in' conversation."

The 'Without You' hitmaker previously admitted his beef with Kelly isn't about him calling his daughter Hailie "hot as f**k" in 2012.

He teased that his problem with the young star is "a lot more petty" than anything he's ever said about the 22-year-old beauty on Twitter, after he hit back with 'Not Alike'.