diff --git a/lib/index.js b/lib/index.js
index 3c7c31f..c699236 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -74,7 +74,7 @@ function Pattern(source, formatCharacters, placeholderChar, isRevealingMask) {
   }
 
   /** Placeholder character */
-  this.placeholderChar = placeholderChar || DEFAULT_PLACEHOLDER_CHAR
+  this.placeholderChar = typeof placeholderChar === 'string' ? placeholderChar : DEFAULT_PLACEHOLDER_CHAR
   /** Format character definitions. */
   this.formatCharacters = formatCharacters || DEFAULT_FORMAT_CHARACTERS
   /** Pattern definition string with escape characters. */