David Furnish and John will produce under their Rocket Pictures banner, along with Matthew Vaughn, who directed John (playing a heightened version of himself) in the Kingsman sequel, and his Marv Films.
Rocketman has been in the works for several years, with The Greatest Showman director Michael Gracey previously attached to helm. Paramount will finance and distribute the feature.
Egerton, who is best known for his work in the Kingsman franchise, will sing John's tunes himself, having already recording songs at Abbey Road Studios.
The Hollywood Reporter spoke with Furnish, who said, "Elton has told Taron, 'Don't copy me. Don't think you have to sing it exactly the way that I sang it. Don't think you have to perform it the way I performed it. I think it's the challenge for the actor to embody the spirit and not get into thinking they have to do an impersonation.'"
This article originally appeared in The Hollywood Reporter.