Paul Scholes and Nicky Butt have revealed a Manchester United legend got knocked out in the middle of a training session during the club's golden years under Sir Alex Ferguson.
Scholes and Butt are two of United's famed Class of '92, and played major roles in the Red Devils dominating the first two decades of the Premier League.
But things don't always run smoothly even for the very best, and Scholes and Butt opened up on the remarkable moment that left a former player seeing stars.
Speaking on the brand new Football's Greatest Eras podcast, the pair recalled ex-United star Brian McClair accidentally flooring Sir Bobby Charlton with a thunderous volley from point-blank range.
Reflecting on the incident, Butt admitted 'I thought he was dead', before explaining in detail: '(It was a) full-on volley from five yards, flush on his head, and completely floored Sir Bobby Charlton, who survived the Munich air disaster.
Paul Scholes and Nicky Butt have revealed Sir Bobby Charlton (right) got knocked out in a Man United training session
They revealed Brian McClair (right) struck a volley that accidentally floored Charlton
Scholes and Butt claimed Charlton joined in training regularly and was still 'brilliant' even in his 60s
They insisted Charlton saw the funny side of being poleaxed by McClair's thunderous volley
'He survived all this stuff but nearly got killed off a Brian McClair volley.'
That training session certainly didn't go to plan, but Scholes and Butt revealed that did not deter Charlton who would train with the squad before 'nearly every European game', and Butt was left in awe of how good the World Cup winner still was decades after his retirement.
'Even though he was at the time, would have been 62 or something, I reckon, or roughly, early 60s, his touch and stuff was brilliant,' Butt said.
'And you're thinking a 60-odd-year-old man could still do that with elite footballers. And it's like, wow.'
Charlton - United's second-highest goalscorer of all-time behind Wayne Rooney - was not the only high-profile name to train with Sir Alex Ferguson's as Simply Red frontman Mick Hucknall also got invited down for a session.
A heavy defeat by Barcelona followed, and Butt claimed Roy Keane had little time for Hucknall due to his tendency to give the ball away, but Butt admitted it was 'surreal' to be rubbing shoulders with such iconic figures.
Charlton passed away last year at the age of 86 following a battle with dementia, but Scholes and Butt insisted he always saw the funny side to being accidentally poleaxed by McClair's volley as they reminisced about the glory days.
'You can say it now, because you know what, Sir Bobby would like it,' Butt added. 'He'd be laughing with us if he was still here.
'But no, to have people like Sir Bobby and Mick Hucknall doing warm-ups with you...when you look back on it, it's a weird dynamic. It's surreal, really, isn't it? It's surreal.'
Football's Greatest Eras with Nicky Butt and Paul Scholes launches on Wednesday 18 September. Episodes will be available every Wednesday. Watch the show on YouTube or listen to it wherever you get your podcasts.