Although many believe that the Happy Birthday song is public property and proceed to belt it out across the world on a daily basis, the rights to the song actually belong to Warner Music. Well, apparently.

Warner/Chappell owns the copyright to the song which is a particularly big money-maker for the company.

However, Warner may have run into a small bit of difficulty in regard to the piece of music.

A filmmaker who requested to use the song in a documentary was asked to pay $1,500 to use the song.  She agreed to the fee but has since filed a lawsuit claiming that Warner’s copyright claim is invalid, according to The Verge website.

The Happy Birthday song itself is a adaptation of a 19th century German song entitled “Good Morning.”The lawsuit which has been filed claims that any claim the company had to the song expired in 1921, which sort of leaves Warner in a bit of hot water.

If the song is found to be in the public domain, Warner could end up paying millions of dollars back to those who have paid copyright fees.

Happy Birthday to you, Happy... wait. How much is this costing us?