NEW YORK: "Happy Birthday to You," the ditty sung around the world in tribute to everyone from toddlers to centenarians, belongs to the public, according to a lawsuit filed on Thursday.

The proposed class action asks a federal court to declare the song to be in the public domain and that Warner/Chappel Music Inc, the music publishing arm of Warner Music Group, return "millions of dollars of unlawful licensing fees" it has collected for reproductions and public performances of the song.

"More than 120 years after the melody to which the simple lyrics of 'Happy Birthday to You' is set was first published, defendant Warner/Chappell boldly, but wrongfully and unlawfully, insists that it owns the copyright to 'Happy Birthday to You,'" the lawsuit said.

A representative of Warner/Chappell was not immediately available to comment on the lawsuit.

The plaintiff is Good Morning To You Productions Corp, a New York company that says it is making a documentary about the song. Facing a penalty of $150,000 if it used "Happy Birthday" without permission, the company said it paid a $1,500 licensing fee in March.

Warner/Chappell has collected at least $2 million annually in licensing fees for the song, according to the lawsuit.

The song was first published in 1893 as "Good Morning to All," and was written by sisters Patty and Mildred Hill, according to the lawsuit. The public began singing the words to "Happy Birthday to You" soon after.

Warner/Chappell's copyright claim stems from its acquisition in 1998 of Birch Tree Ltd, a company that traces its roots to Clayton Summy, according to the lawsuit. Summy bought the rights to "Good Morning to All" from the Hill sisters in 1893.

Robert Brauneis, a professor at George Washington University Law School, said he searched nationwide for evidence of a copyright for a combination of the melody for "Good Morning to All" with the lyrics for "Happy Birthday to You" for an article published in 2009 but did not find any.

Investors led by Edgar Bronfman Jr. bought Warner Music Group from Time Warner Inc in 2004 and sold it to its current owner, privately held Access Industries Inc, in 2011.