diff --git a/modules/lang-painless/src/main/java/org/elasticsearch/painless/Utility.java b/modules/lang-painless/src/main/java/org/elasticsearch/painless/Utility.java
index b965f25bf0e..a03a7b244eb 100644
--- a/modules/lang-painless/src/main/java/org/elasticsearch/painless/Utility.java
+++ b/modules/lang-painless/src/main/java/org/elasticsearch/painless/Utility.java
@@ -30,8 +30,14 @@ public class Utility {
     }
 
     public static char StringTochar(final String value) {
+        if (value == null) {
+            throw new ClassCastException("cannot cast " +
+                    "null " + String.class.getCanonicalName() +  " to " + char.class.getCanonicalName());
+        }
+
         if (value.length() != 1) {
-            throw new ClassCastException("Cannot cast [String] with length greater than one to [char].");
+            throw new ClassCastException("cannot cast " +
+                    String.class.getCanonicalName() +  " with length not equal to one to " + char.class.getCanonicalName());
         }
 
         return value.charAt(0);
diff --git a/modules/lang-painless/src/test/java/org/elasticsearch/painless/StandardCastTests.java b/modules/lang-painless/src/test/java/org/elasticsearch/painless/StandardCastTests.java
index 604e20ad6f9..739d9d021a4 100644
--- a/modules/lang-painless/src/test/java/org/elasticsearch/painless/StandardCastTests.java
+++ b/modules/lang-painless/src/test/java/org/elasticsearch/painless/StandardCastTests.java
@@ -545,4 +545,100 @@ public class StandardCastTests extends ScriptTestCase {
         expectScriptThrows(ClassCastException.class, () -> exec("Number o = new ArrayList(); ArrayList b = o;"));
         expectScriptThrows(ClassCastException.class, () -> exec("Number o = new ArrayList(); ArrayList b = (ArrayList)o;"));
     }
+
+    public void testStringCasts() {
+        exec("String o = 'string'; Object n = o;");
+        exec("String o = null; Object n = o;");
+        exec("String o = 'string'; Object n = (Object)o;");
+        exec("String o = null; Object n = (Object)o;");
+
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = 'string'; Number n = o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = null; Number n = o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = 'string'; Number n = (String)o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = null; Number n = (String)o;"));
+
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = 'string'; boolean b = o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = null; boolean b = o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = 'string'; boolean b = (boolean)o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = null; boolean b = (boolean)o;"));
+
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = 'string'; byte b = o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = null; byte b = o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = 'string'; byte b = (byte)o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = null; byte b = (byte)o;"));
+
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = 'string'; short b = o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = null; short b = o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = 'string'; short b = (short)o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = null; short b = (short)o;"));
+
+        assertEquals('s', exec("String s = 's'; (char)s"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = 'string'; char b = o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = null; char b = o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = 'string'; char b = (char)o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = null; char b = (char)o;"));
+
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = 'string'; int b = o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = null; int b = o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = 'string'; int b = (int)o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = null; int b = (int)o;"));
+
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = 'string'; long b = o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = null; long b = o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = 'string'; long b = (long)o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = null; long b = (long)o;"));
+
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = 'string'; float b = o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = null; float b = o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = 'string'; float b = (float)o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = null; float b = (float)o;"));
+
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = 'string'; double b = o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = null; double b = o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = 'string'; double b = (double)o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = null; double b = (double)o;"));
+
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = 'string'; Boolean b = o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = null; Boolean b = o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = 'string'; Boolean b = (Boolean)o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = null; Boolean b = (Boolean)o;"));
+
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = 'string'; Byte b = o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = null; Byte b = o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = 'string'; Byte b = (Byte)o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = null; Byte b = (Byte)o;"));
+
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = 'string'; Short b = o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = null; Short b = o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = 'string'; Short b = (Short)o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = null; Short b = (Short)o;"));
+
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = 'string'; Character b = o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = null; Character b = o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = 'string'; Character b = (Character)o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = null; Character b = (Character)o;"));
+
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = 'string'; Integer b = o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = null; Integer b = o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = 'string'; Integer b = (Integer)o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = null; Integer b = (Integer)o;"));
+
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = 'string'; Long b = o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = null; Long b = o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = 'string'; Long b = (Long)o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = null; Long b = (Long)o;"));
+
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = 'string'; Float b = o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = null; Float b = o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = 'string'; Float b = (Float)o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = null; Float b = (Float)o;"));
+
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = 'string'; Double b = o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = null; Double b = o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = 'string'; Double b = (Double)o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = null; Double b = (Double)o;"));
+
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = 'string'; ArrayList b = o;"));
+        expectScriptThrows(ClassCastException.class, () -> exec("String o = 'string'; ArrayList b = (ArrayList)o;"));
+    }
 }
diff --git a/modules/lang-painless/src/test/java/org/elasticsearch/painless/StringTests.java b/modules/lang-painless/src/test/java/org/elasticsearch/painless/StringTests.java
index c73d6c2071a..31870b9125c 100644
--- a/modules/lang-painless/src/test/java/org/elasticsearch/painless/StringTests.java
+++ b/modules/lang-painless/src/test/java/org/elasticsearch/painless/StringTests.java
@@ -170,22 +170,22 @@ public class StringTests extends ScriptTestCase {
         ClassCastException expected = expectScriptThrows(ClassCastException.class, false, () -> {
             assertEquals("cc", exec("return (String)(char)\"cc\""));
         });
-        assertTrue(expected.getMessage().contains("Cannot cast [String] with length greater than one to [char]."));
+        assertTrue(expected.getMessage().contains("cannot cast java.lang.String with length not equal to one to char"));
 
         expected = expectScriptThrows(ClassCastException.class, false, () -> {
             assertEquals("cc", exec("return (String)(char)'cc'"));
         });
-        assertTrue(expected.getMessage().contains("Cannot cast [String] with length greater than one to [char]."));
+        assertTrue(expected.getMessage().contains("cannot cast java.lang.String with length not equal to one to char"));
 
         expected = expectScriptThrows(ClassCastException.class, () -> {
             assertEquals('c', exec("String s = \"cc\"; (char)s"));
         });
-        assertTrue(expected.getMessage().contains("Cannot cast [String] with length greater than one to [char]."));
+        assertTrue(expected.getMessage().contains("cannot cast java.lang.String with length not equal to one to char"));
 
         expected = expectScriptThrows(ClassCastException.class, () -> {
             assertEquals('c', exec("String s = 'cc'; (char)s"));
         });
-        assertTrue(expected.getMessage().contains("Cannot cast [String] with length greater than one to [char]."));
+        assertTrue(expected.getMessage().contains("cannot cast java.lang.String with length not equal to one to char"));
     }
 
     public void testDefConcat() {