Newcastle legend Shearer memorably clashed with Keane in the dying embers of a 4-3 victory against United in September 2001. He'd scored the winner late on and then prevented his opponent taking a quick throw-in.
An incensed Keane threw the ball at Shearer before confronting him and pushing him in the face, earning himself a red card before going back for a second bite of the cherry and having to be held back by David Beckham.
Shearer referenced the incident on the latest episode of The Rest is Football podcast when asked what the funniest thing another player had said to him during his career.
"Roy Keane said to me he was gonna knock me out once," he replied, with Lineker joking: "Well you do surprise me. And did he?"
Shearer responded: "Come on." Before Lineker added: "I think I’d back you against him Al, even now. I think people would pay to see that, Shearer vs Keane.
Shearer or Keane - who would you put your money on? Let us know in the comments section.
"You get all these celebrity fights now, get the two of you in UFC or boxing gloves." Shearer didn't seem too keen, arguing: "[I'm] too old for that s*** Gaz."
Keane recently reflected on the sending off himself as he talked through the 13 red cards he was given in his playing days on the Stick to Football podcast alongside Gary Neville, Jill Scott and Ian Wright.
Join the Daily Star's WhatsApp for the sexiest headlines, showbiz gossip and lots more
The Daily Star is now on WhatsApp and we want you to join us!
Through the app, we'll send you the sassiest showbiz stories, some naught headline and a seismic smattering of aliens...along with the latest breaking news of course.
To join our community, all you have to do to join is click on this link, select 'Join Chat' and you're in!
No one will be able to see who has sign up and no one can send messages except for the Daily Star team. We also treat our community members to competitions, special offers, promotions, and adverts from us and our partners.
If you don’t like our community, you can check out any time you like. To leave our community click on the name at the top of your screen and choose Exit group. If you’re curious, you can read our Privacy Notice.
"That was more about the team, our team," he argued. "We gave away a goal towards the end. Wes [Brown] was poor for the goal, I was more angry at him. And you know when they wouldn't give you ball back, one of them."
Shearer claims Keane waited for him in the tunnel post match. The former United skipper still doesn't see eye-to-eye with him, having previously admitted he wished he'd punched him as he would've got the same three-match ban anyway.