The rappers have been making headlines in recent months for their ongoing digs at one another, all stemming from a tweet MGK posted six years ago. They've publicly criticized each other through music and in various interviews, and it doesn't sound like their beef is ending anytime soon.
Now, ET's breaking down everything you need to know about what led to all the tension between the artists, and where their reignited feud stands now.
What Ignited the Feud
It all started in May 2012 when a 22-year-old Kelly saw a picture of Eminem's then-16-year-old daughter, Hailie Jade (now 22). At the time, he tweeted, "I have to say, she is is hot as f**k, in the most respectful way possible cuz Em is king."
"It all started with the daughter thing," Kelly, now 28, recalled in a new interview with Power 105.1 radio show The Breakfast Club on Thursday. "I didn't know how old she was. I made a comment, I didn't feel like it was disrespectful but I'm a father, I have a 9-year-old daughter, I get it, 100 percent, and man to man, I'll tell you, I apologize, can I take the tweet down? Sure. But public apology? Come on...We're talking about the same guy who s**ts on dead people."
"It was a silly comment to have started all of this," he added. "It's something silly to trip on. I get it if it was like, you know, gruesome words were used or like, there was, you know, sexual implications in it. [I just said] she's hot."
What Machine Gun Kelly Has Said About Eminem
In that same interview, MGK said he "handled" the Hailie situation with Eminem's manager six years ago "behind the scenes," and has tried to talk with the rapper directly, but claims he "doesn't want to have a conversation."
"F**k you. You blew it," he exclaimed. "You blew it. It's cool 'til it ain't. I wish he would shut the f**k up."
"Use what I've done with this Em situation as an example to the youth," he continued. "Let's be clear, stand up to people that are f**king with you and stand up with a purpose."
In addition to the Hailie situation, Kelly also accused Eminem in 2015 of having him blackballed from the radio channel Shade 45. "Certain people won't even listen or review this joint," he said during an appearance on Hot 97 while promoting his second album, General Admission. "Certain places you won't even hear Machine Gun Kelly on... F**k anybody who's trying to take food off not just my plate, but a whole city. It's more than just me. Let us win. Help us, man."
Eminem Takes a Dig at MGK Through Music
In August of this year, Eminem dropped a surprise album, Kamikaze, which features a track called "Not Alike." He directly calls out Kelly in the song, rapping, "And I'm talkin' to you, but you already know who the f**k you are, Kelly."
"I don't use sublims and sure as f**k don't sneak-diss," he continues, "but keep commenting on my daughter Hailie."
A few days later, Kelly attacked "the big bad bully of the rap game" in a track called "Rap Devil," a play on Eminem's "Rap God" off his 2013 album, The Marshall Mathers LP 2. In the song, Kelly criticizes everything from Em's "weird" beard, to his "corny hats" and age -- "Em, you're pushing 50" -- to his sobriety.
"Mad about something I said in 2012 / Took you six years and a surprise album just to come with a diss," he raps. "Homie we get it, we know that you're the greatest rapper alive / F**king dweeb, all you do is read the dictionary and stay inside."
Kelly also claimed again in the track that he can't go on Shade 45 because Eminem "blackballed" him. He also took to Twitter to explain why he came out with the song.
"I'm standing up for not just myself, but my generation," he tweeted. "I'm doing the same s**t you did back in ur day. Life is still real on my side, and I had to take time from the grind to defend myself from someone I called an idol. love, Rap Devil."
im standing up for not just myself, but my generation. im doing the same shit you did back in ur day. life is still real on my side, and i had to take time from the grind to defend myself from someone i called an idol. love, Rap Devil.
Things got heated even more when Eminem released "KILLSHOT" on Sept. 14, a track that slams Kelly from beginning to end.
"Realized I forgot to call you back / Here's that autograph for your daughter, I wrote it on a Starter cap," he raps. "Stan, Stan, son, listen, man, dad isn't mad / But how you gonna name yourself after a damn gun and have a man bun?"
"So what good is a f**kin' machine gun when it's out of ammo," he adds. "Had enough of this tatted-up mumble rapper."
Following its release, Em sat down for an interview with Sway Calloway, where he explained why he took aim at Kelly.
"The reason that I dissed [Kelly] is because he got on," he said. "First what he said, 'I'm the greatest rapper alive since my favorite 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**king think about you?" he continued. "You know how many f**king rappers are better than you? You're not even in the f**king conversation."
Eminem also opened up about now being in a catch-22 situation with the rapper. "Now I'm in this f**king weird thing because I'm like, I have to answer this motherf**ker, and every time I do that, it makes that person -- as irrelevant as people say I am in hip hop, I make them bigger by getting into this thing where I’m like, I want to destroy him, but I also don't want to make him bigger because now you’re a f**king enemy. I'll leave it at that."
Machine Gun Kelly Gets the Last Laugh (For Now)
When Kelly opened for Fall Out Boy in Orlando, Florida, earlier this week, he wore a T-shirt of Eminem's "KILLSHOT" cover art, posing for photographers with his middle fingers high in the air.
He later posted a series of pics from the concert to Instagram, writing, "He missed. #legshot #rapdevilstillNUMBERONE #letstalkaboutit."
Then, in his interview with The Breakfast Club, MGK made it clear that he didn't take too much offense to Eminem's latest digs. "You want to talk about man buns?" he said. "You want to talk about a hairstyle I wore for a movie, a blockbuster movie, shout-out Nerve, and a 10-episode Showtime series called Roadies? I'm an actor, homie. How disconnected are you?"
"You called me a 'mumble rapper'?" he continued. "Can we just pour some out for this old dumba**? I can't even."
Back in June, Hailie gave a rare interview with the Daily Mail, where she opened up about growing up in the spotlight with her famous dad.