Joke: Creating A Porn Flick

A pianist was hired to play background music for a movie. When it was completed he asked when and where he could see the picture. The producer sheepishly confessed¹ that it was actually a porno² film and it was due out in a month.
A month later, the musician went to a porno theatre to see it. With his collar up and dark glasses on, he took a seat in the back row, next to a couple who also seemed to be in disguise³.
The movie was even raunchier than he had feared, featuring group sex, S/M and even a dog.
After a while, the embarrassed pianist turned to the couple and said, "I'm only here to listen to the music."
"Yeah?" replied the man. "We're only here to see our dog."