Feelgood 1946 Christmas classic It's a Wonderful Life is to get an unlikely sequel more than 60 years on, it has been revealed.

It's a Wonderful Life: The Rest of the Story is being billed as a continuation of the story of downcast bank manager George Bailey, played memorably by the late great James Stewart in Frank Capra's original. Or at least, that of his descendants. While Stewart passed away in 1997, producers have recruited original cast member Karolyn Grimes, who played George Bailey's daughter Zuzu, to return.

It's a Wonderful Life follows Bailey as he sets out to kill himself on Christmas Eve but changes his mind thanks to the intervention of a guardian angel who helps him realise he has made a difference in the world. The sequel, which riffs on Charles Dickens' A Christmas Carol, will centre on Bailey's mean grandson. In a not-so-feelgood twist, it reportedly sees him visited by his aunt Zuzu, now an angel, who shows him how much better off the world would have been had he never been born.

The new film is being put together by Allen J Schwalb, whose Florida-based Star Partners firm financed Rain Man and The Color Purple during the 1980s. He will work with Bob Farnsworth of Nashville-based commercial music specialists Hummingbird Productions on the project. The latter co-wrote the screenplay for the followup after discovering that Capra's film was out of copyright in the US.

"It's a Wonderful Life is about showing a good guy can win. And with Scrooge, you have a person that is not a good guy but he changes," Farnsworth told The Hollywood Reporter. "This story is about the amazing human capacity to forgive when we see someone change for the better."

Of suggestions that audiences may balk at seeing one festive favourite - let alone two - revived in unfamiliar form, the screenwriter said: "Look, no one can make another It's a Wonderful Life. But our story is solid, and we are going in with our eyes open. There is no doubt about it, there will be a ruckus. But I have this motto: All it takes to be a leader is to have a cause you believe in. And the stronger you believe in the cause, the more adversaries you will have. And we strongly believe in this."

Farnsworth received help on the screenplay from Martha Bolton, who worked with Bob Hope as a staff writer on the comedian's specials. Producers are currently on the hunt for a director and plan to secure a budget in the $25-32m range. They hope to bring the sequel to the big screen in 2015.

Capra's It's A Wonderful Life regularly tops polls of favourite Christmas movies on both sides of the Atlantic.

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• What should be the plot of the sequel? Submit your ideas – even a script sample – below, along with any casting suggestions