"I can't hold a tune to save my life," Tom said as he discussed the film, currently titled Rocketman.
But it doesn’t seem to be holding The Dark Knight Rises actor back as he admitted that if he doesn’t sing he will have failed.
Elton John and Tom Hardy
When asked if he will be singing in the new film, he said: "Yeah, I hope so. Otherwise I'll have probably failed, right?"
Speaking to the Wall Street Journal, he went on: "But that's terrifying me,” before continuing: “God knows how I'm going to do that."
Rocketman will start shooting late in 2014.
The film is being made with the co-operation of Sir Elton, 66, who will work as an executive producer on the project. It will follow Reg Dwight's journey from child piano prodigy to global superstar, now known by millions as Elton John.
Tom recently admitted becoming a father was the only thing that saved him from the drink and drugs addiction that threatened to ruin his life.
"I had no idea how to handle the industry, to interact with producers, executive producers, studios… I was 24 – punching above my weight," he told the Metro newspaper.
"And it’s taken being someone’s dad, being divorced, going to rehab, having mortgages, playing different characters, doing theatre, waiting and then it not happening. And then doing rather well at something, enjoying my character work, but it not being a huge amount of money."
Tom will also star in a new film based on the life of London gangsters Reggie and Ronnie Kray, and he has joined the cast of BBC hit show Peaky Blinders, where he will be working with his fiancée Charlotte Riley.