Katy Perry is now one of several musicians expressing outrage at President Trump's administration for using her song to promote a policy she does not agree with.

Over the past couple of years, a lot of musicians have called out the White House publicly for unauthorized use of their songs.

I am deeply appalled and angry to see Firework used on the @WhiteHouse TikTok account as a backing track for video footage of military strikes. I did not approve this, I was not asked, and I absolutel...