“Happy Birthday” has been noted by the Guinness Book of World Records as the most recognized song in the English language. While a school teacher named Patty Smith Hill and her sister Mildred Hill are noted as the songwriters, its copyright control might be confusing as something authored so long ago still necessitates a license fee from publisher Warner/Chappell Music whenever it is publicly performed.

A new lawsuit is intended to have “Happy Birthday” declared as belonging to the public domain. The proposed class action is brought by a film company that is working on a documentary about the famous song. The company claims it has “irrefutable documentary evidence, [which] shows that the copyright to ‘Happy Birthday,’ if there ever was a valid copyright to any part of the song, expired no later than 1921 and that if defendant Warner/Chappell owns any rights to ‘Happy Birthday,’ those rights are limited...”