It was needed in "School of Rock". 

Remember the movie "School of Rock"? It was a pretty rocking movie with an awesome sound track including Led Zeppelin's "Immigrant Song".

But here's the thing... Led Zeppelin almost never lets anyone use their music in movies. (Advice to young musicians... own your own songs.) It was crucial to have the Gods of Rock in this movie so Jack Black was asked to beg Led Zeppelin for use of the song. It was awesome and funny which is quintessential Jack Black.

Who could say no to this?