Paramount Studios have threatened to take legal action over a proposed sequel to the 1946 film It's A Wonderful Life.
The forthcoming film, starring Karolyn Grimes - who starred in the original movie - was announced by Hummingbird Productions earlier this week.
But Paramount said no project could proceed without the "necessary rights", which are owned by the film studio.
"We will take to take all appropriate steps to protect those rights."
The original film, directed by Frank Capra, saw James Stewart playing George Bailey, a family man in the depths of despair who is assigned an angel to show him what life would have been like if he never existed.
Set on Christmas Eve, the film has gone on to become a festive classic, despite being poorly received on its release.
Tennessee-based Hummingbird Productions announced on Monday that it had teamed up with Star Partners for a follow-up film based on Bailey's grandson.
It said Grimes, who played Bailey's daughter Zuzu in the original movie, would star in the sequel as an angel.
Hummingbird's Bob Farnsworth previously told The Hollywood Reporter that the rights to It's a Wonderful Life were in the public domain.
"It's a Wonderful Life is about showing a good guy can win," Farnsworth told the industry paper.
He said he had written a screenplay with Martha Bolton entitled It's a Wonderful Life: The Rest of the Story, and was hoping it would be released in December 2015.
A lapsed copyright saw the film repeatedly broadcast on TV at Christmastime during the 1970s and '80s.
However, Paramount is understood to have controlled the rights for the past 14 years, after the studio acquired Republic Pictures as part of its acquisition of Spelling Entertainment in 1999.
Frank Capra's son, Tom, told the Associated Press that if his father was still alive, he would have deemed the sequel "ludicrous".
"Why would you even attempt to make a sequel to such a classic film?"