Chubby Checker, the legendary singer of “The Twist,” is suing the makers of an app that estimates a man’s penis size.

The Chubby Checker app (Get it? Chubby Checker?) claims to estimate the size of a man’s member based on his shoe size.

The singer claims his name is trademarked and shouldn’t be used by this app – or any other for that matter.

The lawsuit asks for the companies to immediately stop using the Chubby Checker name and seeks all profits the defendants have made off the app.