The Australian actors may star together in Les Miserables as rivals Jean Valjean and Inspector Javert, but Hugh revealed they are actually good friends in real life.
"Russell and I actually became very close friends. We were good friends before," he told Entertainment Weekly.
"Russell has given me advice several times at key moments in my life that helped with my career. I also owe him because two of the biggest roles I've ever had in my life, he turned down - and suggested me for them."
Hugh - who plays Jean Valjean in Tom Hooper's big-screen adaptation of the hit musical - admitted that it was challenging playing enemies on screen.
"We really pushed each other. That rivalry at the beginning, it really is a constant throughout. It had to be strong, and it's really one of the spines of the story, that runs from beginning to end. It's a real challenge, and we were there for each other," he explained.
Hugh said to Deadline.com: "When I saw it in its entirety - I knew intellectually it was a big risk - I said 'Wow, man. This is massive, a big bone to chew on, that one'. I felt so proud to be part of it."