The Brit has been cast as the flamboyant performer in Rocketman, a new film which will detail the singer's life after leaving rehab in 1990.
However, Hardy fears he will infuriate fans unless he learns how to sing properly to portray the Your Song legend on screen.
He tells the Wall Street Journal, "(I will have to sing) otherwise I'll have probably failed, right? But that's terrifying me. I can't hold a tune to save my life. God knows how I'm going to do that.
"But then I couldn't cage fight before I'd gotten in with (2011 fighting film) Warrior. And I still can't. I'm not supposed to be a cage fighter. I'm only playing one."