Bradley told the new issue of America's Esquire magazine: "Russell Crowe. S**t. He is. Next level."
The 36-year-old actor – who has recently been romantically linked with actress Olivia Wilde – is also critical of himself, admitting he thinks he could work harder.
He exclaimed: "Oh my God, I am so f**king lazy."
However, those who know the star disagree.
The publication reports three of his friends told them: "There is no off switch for his career," while his former rowing crew coach at Georgetown University spoke of his determined streak.
He said: "There is a fierce, fierce, fierce fire in that guy. That determination of his — nobody should ever underestimate that
Bradley showed off his dramatic side earlier this year in thriller 'Limitless' but he insists the success of the film hasn't changed him or his career.
He said: "Since 'Limitless' opened, my agent calls me every morning and asks, 'Do you feel any different?'
And I'm like, 'Nope. Do you feel any different?' "