diff --git a/src/lib/js/string.rs b/src/lib/js/string.rs
index ea3cd13651..d1db2ae91e 100644
--- a/src/lib/js/string.rs
+++ b/src/lib/js/string.rs
@@ -387,7 +387,7 @@ fn string_pad(
 /// https://tc39.es/ecma262/#sec-string.prototype.padend
 pub fn pad_end(this: Value, _: Value, args: Vec<Value>) -> ResultValue {
     let primitive_val: String =
-        from_value(this.get_private_field(String::from("PrimitiveValue"))).unwrap();
+        from_value(this.get_internal_slot("PrimitiveValue")).unwrap();
     if args.len() < 1 {
         return Err(to_value("padEnd requires maxLength argument"));
     }
@@ -407,7 +407,7 @@ pub fn pad_end(this: Value, _: Value, args: Vec<Value>) -> ResultValue {
 /// https://tc39.es/ecma262/#sec-string.prototype.padstart
 pub fn pad_start(this: Value, _: Value, args: Vec<Value>) -> ResultValue {
     let primitive_val: String =
-        from_value(this.get_private_field(String::from("PrimitiveValue"))).unwrap();
+        from_value(this.get_internal_slot("PrimitiveValue")).unwrap();
     if args.len() < 1 {
         return Err(to_value("padStart requires maxLength argument"));
     }