Manchester United legend Roy Keane admits he regrets turning down the chance to join Real Madrid and says that his decision to reject the Spanish giants was due to the "fear of the unknown".
The former Red Devils captain made the revelation in his new autobiography 'The Second Half' which has courted a number of newspaper headlines over the past few days following its release earlier this week.
Keane touches on a number of high-profile incidents that occurred during his colourful career at Old Trafford, including his public falling out with Sir Alex Ferguson, altercations with ex-teammates, and horror tackle on Alf-Inge Haaland.
However, one interesting period that some fans perhaps might not know is that the former Republic of Ireland international snubbed an opportunity to move to the Santiago Bernabeu in the summer of 2005, before his final season as a professional footballer.
The 43-year-old - who now works as assistant manager to Paul Lambert at Aston Villa - had enjoyed 12 years of glory at Manchester United when the call came from Real Madrid, and Keane reflects that he did not fully appreciate the offer of a new challenge in a different country.
"Michael [Kennedy: Keane's agent] had given me a heads-up that Emilio Butragueno would be phoning, so I took my mobile phone everywhere with me," he wrote, as transcribed by Goal.com.
"And - how's your luck - he rang me while I was sitting on the toilet. He said: 'Look Roy, we'll be glad to have you.' The club's board just had to sanction the deal.
"I should have appreciated Real's offer more. It was the most attractive challenge in front of me but I didn't accept it."
Keane admits that he felt he would not have been able to give his best at that stage of his career, but accepts that it was perhaps the wrong decision to turn his back on a club as illustrious as Real Madrid.
"In hindsight, I should have said to myself: 'Go, go to Spain, live there for a year and a half, learn the language, learn the culture,'" he added. "[But] I took a negative approach.
"The weather and the training might have given me another lease of life, another two years of playing. As much as anything else, it was fear that decided me - fear of the unknown."
Instead Keane moved north of the border to join Scottish Premier League giants Celtic, ending his career with the Bhoys in 2005/06, but he'll always be left wondering what might've been had he chosen to move to the Spanish capital and hang up his boots in La Liga.
Keane's book has shocked many with his open and honest account of various events which occurred over the years, and his inner feelings - now, and at the time - regarding them.
Many supporters might disagree with the way the Manchester United legend carried himself during his playing career, but few can argue that his no-nonsense approach is refreshing at a time where players are increasingly guarded and protected against making comments to the media.