I get excited just thinking about rewriting the lyrics to '
rewrite the stars', but the legal side is a little less glamorous than belting it out on a stage. Lyrics and melody are both protected by copyright, which means the original writers and their publisher control whether someone can make a new version of the words. If you want to keep the music and just change the words, that's called a derivative work — most publishers won't let you do that without explicit permission. Even putting the song in a video needs a sync license, which is separate from the usual cover permissions.
If you're planning a simple live cover at a bar or a coffee shop, the venue often already has a public performance license through a PRO like ASCAP, BMI, or PRS, so changing lyrics still complicates things because those licenses apply to the original composition. For recorded releases, a mechanical license covers covers with the original lyrics, but once you alter the words you need to negotiate directly with the publisher. Parody can sometimes fall under fair use in the U.S., but it's narrow and risky — courts look at transformation and market harm, and a musical parody that competes with the original could lose.
My practical tip: look up the song on PRO databases to find the publisher, ask for permission for any changed lyrics, and be ready to discuss splits or a derivative license. If you're just doing a private, non-monetized rewrite for fun with friends, it’s unlikely to trigger enforcement, but posting it publicly — especially monetized on platforms like YouTube or streaming services — is a different story. I still love tinkering with lines in my head, but I try to clear it before sharing publicly, because preserving the creators' rights feels fair to me.