Cahill - who qualified thanks to his Irish grandad - was approached to play for Eire when Steve Staunton was in the hot seat.
"I saw him when I was playing for the reserves and then I started to get more and more first-team games.
"He knew Kevin McDonald, who was his Ireland No.2 and he was our reserve team coach at Villa.
"When I made the first team he kept coming to watch me play.
"He asked me if I would like to play for Ireland when I was 20 - but it just didn't feel right at all.
"The link comes from my grandfather, who was Irish - but he died before I really got to know him so I've only known my family as being English really.
"Also it would have felt odd because I'd already played for England Under-20s and Under-21s and so I thought that I might one day get that chance to play for the full national side."