Disney and 2-time EGOT winner Robert Lopez are being taken to court by a songwriter that claims his 2001 track was stolen and used in "Frozen 2" ... and he allegedly came to the conclusion while in the theater with his kid.
According to legal docs, obtained by TMZ, musician Daniel Grigson first heard the song "Some Things Never Change" while watching "Frozen 2" in theaters at the end of November 2019 ... and as the song was being performed, he says he got up out of his seat in shock.
The docs say the track's beat, rhythm, feel, theme, and words caught him off guard -- because Grigson claims it's basically IDENTICAL to his song, "That Girl," from decades ago.
Grigson says his eyes were wide open while standing in the theater -- once he sat back down with his head in his hands, he claims his 11-year-old daughter leaned over to him and said, "Dad, Disney took your song."
Grigson says he hired an analyst to compare the 2 tracks -- coming to the conclusion that not only do the songs sound alike, but both are also similar on a technical level.
He now wants Disney and Lopez to fork over profits made from the song ... and for the company to stop using the track.