Looks like everyone can now sing the "Happy Birthday" song for free.

In a surprise ruling Tuesday, U.S. District Court Judge George H. King granted summary judgment to filmmakers like director Jennifer Nelson who had challenged Warner Chappel Music's decades-old copyright claims to one of the best-known English-language tunes.

Warner Chappel reportedly earns about $2 million annually in royalties on public performances of the song since the company acquired Birch Tree Group, the successor to Clayton Summy Co., the song's original copyright owner.

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King ruled that a copyright filed by the Summy Co. in 1935 granted only the rights to specific arrangements of the music, not the actual song itself.

"Because Summy Co. never acquired the rights to the Happy Birthday lyrics, Defendants, as Summy Co.'s purported successors-in-interest, do not own a valid copyright in the Happy Birthday lyrics," he said in his opinion.

Due to the ruling, movies, TV shows and plays will be free to use the song in public commercial performances without having to pay royalties. Nelson had sued in 2013 over Warner Chappel demands for a six-figure licensing deal.

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In a statement, Nelson called the decision a "great victory for musicians, artists and people around the world who have waited decades for this."

In addition, her attorneys have said that they will seek to recover millions in dollars in royalties that Warner Chappell has earned on the song via a class-action lawsuit.