Eminem New Album 2013: Justin Bieber vs. Slim Shady 'Lose Yourself' VIDEO Goes VIRAL, 'Believe' Crooner 'Bombs' Rap Song Cover, Will Em Retaliate with 'Diss' Lyrics?

Check out this little Youtube gem posted back in 2010...

Yup - that's 19-year-old "Believe" crooner Justin Bieber busting out a rhyme to Eminem's hit song "Lose Yourself" during a concert in DETROIT. Should Slim Shady be honored, or just plain insulted?

Well, several Youtube fans weren't impressed. Don't mess with Eminem City, Biebs:

lq994: "HOW COULD HE USE EM's BEST SONG TO F#CK IT UP, AND HE DID IT IN SHADY's CITY - DETROIT. F#CK JB!"

kierondunk: "Bieber has outdid himself here... this is the lowest of the low."

Tunahan Seferler: "Fuck Jb fuckin pu##y."

Keep701: "Sorry 'bro,' but your balls aren't even close enough to dropping to imitate something that you'll never be. Poser."

1stLinkinparkfan: "[WTF], I hate him more, it's Eminem city, Eminem's best song, and what??? He came there to sing it thinking it'd be cool. -.-"

Ouch.

But such hate doesn't seem to have bothered the Biebs... he performed the same Eminem song AGAIN on Sunday (July 28) in Detroit:

Peyman Shahsavarkhani: "anybody else noticed that he got the very first line wrong? he says: 'his palms are heavy' F#CKIN FA#GOT dont come to the d and disrespect eminem. u better know his lyrics before you try to cover it in his hometown f#ckin b#tch."

AlanVillarreal12: "this no its rap... is s#it."

But do Mstars readers think Shady agrees with the rather negative backlash? Admittedly, the Biebs did sort of bomb the rap cover. Just check out this "Justin Bieber vs. Eminem: 'Lose Yourself'" version that's since gone viral online:

Details surrounding Em's highly-anticipated new album still remain unknown. But would fans like to see a song "bashing" Bieber's attempted rapping? Shady's known to "diss" fellow celebs in his lyrics... just check out verses from Em's new song "Symphony in H" off of Tony Touch's latest mixtape "The Piece Maker 3: Return of the 50 MCs" -

Here's one line... "Yo wait, I'm an a-hole / Devil with a halo / Hell yeah, I'd nail J.Lo ... to the railroad!"

Yeah... Bieber might have it coming to him.

But fans will just have to wait and see... there's still no official release date for Em's 2013 album.