John Cena’s feud with The Rock during the early 2010s produced some of the most memorable moments in WWE TV history.

Cena even brought back the old Dr. of Thuganomics gimmick that he made his name with as part of his feud with the WWE icon, producing an incredible segment in 2012.

So, what on earth happened when John Cena embraced his past as part of, without a doubt, one of the biggest feuds of his career?

The Rock and John Cena's iconic WWE feud

Just under three weeks out from their “Once in a Lifetime” billed match (they had a rematch the very next year), the two men faced off in a “Rock and Rap concert.”

This gave both men the opportunity to express themselves in their preferred musical style – The Rock with a guitar concert and John Cena with a battle rap.

This allowed Cena to bring back the gimmick that put him on the map. He had previously been the Dr. of Thugnanomics from 2002 to 2005 on Smackdown where he enjoyed enormous success.

You can check out the footage of Cena's 2012 rap below...

Video: John Cena's hilarious 2012 WWE rap

The familiar “Word Life” theme song played out in Cleveland, Ohio as the Dr. made his way to the ring and immediately broke into a 2-minute rap incorporating numerous slurs.

Cena scathing rap on The Rock

His opening lines referenced Lebron James leaving the Cleveland Cavaliers and “taking his talents to South Beach” and the Miami Heat two years prior. At the time, James was public enemy no.1 in his hometown, well until he returned in 2014.

Cena also had lines about The Rock having his promo scribbled down on his arm the previous week, his pectoral surgery in 1998, his films “G.I. Joe” and “Tooth Fairy.”

He finished off with a line referencing nuts, a staple of his rapper gimmick in the Ruthless Aggression era, and something that was out of place in the now-PG era.

John Cena brought back his old gimmick for his 2012 feud with The Rock

Some of Cena's best lines

"Rock wanted me to write his song tonight but I would never be his mouthpiece
'Cause Rock's like LeBron James; he took his talent straight down to South Beach"

"And for the past few weeks, Rock's been legitimately pissed
If you get stuck singing your song tonight Rock, it's all in the wrist"

"Could we please have a week where you don't come out here and choke? You may be G.I. Joe this summer, right now you're a "G.I. Joke""

"And after April 1st, you won't be making no more movies, You're going to need surgery on your face just like you had it on your boobies"

"Team Bring It? He's Team Lost It and the truth is getting scary
'Cause they weren't chanting "Rocky" last week, they were chanting "Tooth Fairy""

"And no, no, I don't have balls but I got something in their place
I'ma beat your ass at WrestleMania and put my nuts dead in your face!"

The segment and the feud as a whole brought back an edgier side to Cena, something that fans had been longing for given his white bread babyface hero role of the previous six years.