During their respective careers on the pitch, Roy Keane and Alan Shearer established themselves as Premier League icons whilst playing for two of England's biggest clubs.
And even though their playing days came to an end long ago, the duo are still at top of the league when it comes to football pundits.
Keane and Shearer have embarked on the same career path following their decision to hang up their boots; Keane is one of Sky Sports' most explosive pundits and Shearer one of the BBC's biggest names.
But both still have that competitive edge that made them so revered as players - so much so that a rivalry which was forged on the pitch over two decades ago is still raging on to this day from their respective TV studios.
The spark that ignited the fiery feud occurred 21 years ago today. A last-gasp clash in the dying embers of Newcastle's 4-3 win against Manchester United seemed innocuous enough at first glance; Shearer did his utmost to prevent Keane from taking a quick throw in a bid to find an equaliser by throwing his hands in the air.
But Keane absolutely blew his fuse. What followed was a remarkable on-field clash between the pair which saw the fiery Irishman sent off - much to the delight of the St. James' Park faithful. Incensed by his dismissal, Keane swung for the Newcastle skipper and had to be restrained by a number of his United teammates.
But the drama didn't end there. Keane was waiting for Shearer in the tunnel after the match - an incident that Shearer recalled last year. He told The Athletic: "When the final whistle went, Roy was standing at the top of the stairs waiting for me.
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"I'm pretty sure a few more choice words were exchanged, there was some bustling and scrambling, but there were way too many people between us for anything physical to actually happen. That's usually how it pans out in football."
Keane has spoken previously on why he decided to swing for Shearer. "I lost my temper, we were losing 4-3, I think, in the last minute," Keane said previously.
"If you're going to get sent off, the worst thing is, I pushed him. If you're going to get sent off you might as well punch him properly because you're going to get the same punishment.
"You might as well be hung for a sheep as a lamb. That's what I was thinking afterwards. It was just a push. It was ridiculous."
The former England striker went on to insist that he didn't view Keane as an "enemy" - but comments Keane made earlier this year suggests that Shearer's stance isn't a mutual one.
Although the pair now work for rival broadcasters, there was a time when they were both doing punditry work for the BBC. And When the ex-midfielder was asked on 'The Overlap Live': if any of the feuds from his playing days had led to issues in the TV studio, he quipped: "Yeah, most weeks!
"There's one or two I've done games with where we couldn't get over that hurdle of what happened in the past." When he was pushed to reveal a name, Keane simply said: "Shearer... forget it."
And despite the fact that Shearer had claimed that any issues between the pair were non-existent, he also appeared to reignite the feud earlier this year when he changed his story over the post-match dramatics before the pair on that fateful afternoon on Tyneside.
Speaking on the BBC prior to the FA Cup final in May, Shearer, who previously claimed that Keane's "bark is worse than his bite", quipped: "Roy didn't like me for some reason, I don't know why. He was getting beaten that day, that's [probably] why.
"We were winning the game and there was only a minute left. I was waiting for him in the tunnel - he ran away!"
While it's unclear who was waiting for who in the tunnel two decades ago, we can agree on one thing - we wouldn't fancy a scrap with either of them.
