Musician Skylar Grey -- Hey Kid, Quit Using My Fake Name

Musician Skylar Grey is claiming a 14-year-old street artist has ripped off her name, and she wants him to change it ... or else.

According to a letter obtained by TMZ ... Skylar wants 14-year-old Skyler Grey (with an 'e') to go by a different name because it's causing confusion -- she suggests "Skyler Grey Arthurs" or "Skyler G" or just "SG."

Here's the irony ... Skylar Grey isn't even HER legal name. It's actually Holly Hafermann. Nonetheless, she's already trademarked it and used it in all her videos and marketing.

The REAL Skyler Grey just so happens to be a legit prodigy himself ... he's sold his street art to Snoop Dogg, The Game and other big names.

We're told Skyler the kid refuses to fold.

You're move, fake Skylar.