Roy Keane will always be regarded as one of the most iconic players of the Premier League era.
He won numerous titles under Sir Alex Ferguson at Manchester United before leaving the club under controversial circumstances after 12 years.
Roy keane opens up on turning down Real Madrid, Bayern Munich
Speaking on the Stick to Football podcast, which he co-hosts with Gary Neville, Ian Wright, and Jamie Carragher, Keane said the Celtic move was an "emotional" decision.
'I had offers from Real Madrid and Bayern Munich when I left Manchester United.
"I went to Celtic instead. It was a bit [emotional], which is fine, I don’t mind making that kind of decision. But I was 34, I just thought, would I go [to Real] and have an impact?"
Keane spent six months at Celtic, making just 13 appearances due to injuries before calling time on his career.