David Moyes is now best known for his short spell as Sir Alex Ferguson's replacement as Manchester United manager, but it's easy to forget that he did actually have a relatively successful playing career before turning his hand to management.
Moyes joined Celtic aged 17, and went on to have spells with Cambridge United, Bristol City, Shrewsbury Town, Dunfermline Athletic and Hamilton Academical before his move to Preston North End.
It was at Deepdale where Moyes really made his name, making over 150 appearances for the club as well as becoming captain of the Lilywhites before his ascension in coaching.
The Scot was a centre back in his playing days, and in this month's edition of FourFourTwo magazine, Moyes told them about his experience of playing in an Old Firm derby for Celtic against bitter rivals Rangers.
"I played in a couple of Old Firm games and they were sensational. The level of the derby in Glasgow would be up there with anywhere in the world. It was ferocious," said Moyes.
"Celtic were ahead of Rangers then. That changed in the '90's, but Celtic were right for my development and it was a privilege to be there," he added.
Moyes' comments are particularly topical given that Celtic just beat Rangers 2-0 in the Scottish League Cup at Hampden Park.
The gulf between the two teams was noticeable, and the game was a far cry from the glory days of the fixture, but tensions between the two sets of fans is still high.
That makes the fixture one of the biggest in football, with few games around the world able to replicate the rivalry between the two clubs - and as Moyes remarked, it's a sensational derby.