Everybody knows the song "Happy Birthday To You". It is the most popular and most often sung song in the English language. It is also now part of a legal case. A New York film company called Good Morning To You (GMTY) Productions has opened a lawsuit that says the song belongs in the public domain. This means anyone can use it because there is no copyright on it. However, the record label Warner Music says it owns the copyright to the tune. GMTY is making a documentary about the history of the song and had to pay Warner Music $1,500 to use it. If it didn't pay, it could have got a penalty of $150,000. The boss of GMTY was angry about this fee and took the case to a court in New York.

The melody of "Happy Birthday To You" comes from the song, "Good Morning to All". This was written in 1893 by two sisters from Kentucky, USA. They wrote it because they thought it would be easy for young children to sing. The words to "Happy Birthday To You" were added to the tune around a decade later. One of the most famous performances of the song was when Marilyn Monroe sang, "Happy Birthday, Mr. President" in a sexy voice to John F. Kennedy in 1962. GMTY says any copyright on the song ran out almost 100 years ago. The company wants Warner Music to return the millions of dollars it has collected for the song. Warner Music has so far stayed quiet and has not commented on the court case.