The Australian's actor's mother lives in Norwich, England and he has become a fan of Norwich City Football Club over the years, even visiting the team's home ground, Carrow Road.
He was offered the chance to become a part-owner of the club a year ago, but turned the offer down.
The team subsequently won a promotion which elevated them to playing in England's top league, and Jackman admits he should have accepted the deal.
He tells BBC Radio Five Live, "Sometimes I make big mistakes. I got a letter about a year ago saying, 'Being such a huge Norwich City fan would I like to be a celebrity investor?', like a small part-owner. I said, 'I think that's a little stretched, I've been to Carrow Road once, my mum took me', so I decided not to invest. And since then they're on a run, so what do I know?
"People say to me about these underdog stories in Hollywood, 'It never happens in real life', but hey, Norwich City are in the Premier League."