diff --git a/src/Illuminate/Validation/Rules/DatabaseRule.php b/src/Illuminate/Validation/Rules/DatabaseRule.php
index ab5e13d6468d..e9b110ba917f 100644
--- a/src/Illuminate/Validation/Rules/DatabaseRule.php
+++ b/src/Illuminate/Validation/Rules/DatabaseRule.php
@@ -62,11 +62,11 @@ public function resolveTableName($table)
             return $table;
         }
 
-        $model = new $table;
+        if (is_subclass_of($table, Model::class)) {
+            return (new $table)->getTable();
+        }
 
-        return $model instanceof Model
-                ? $model->getTable()
-                : $table;
+        return $table;
     }
 
     /**
diff --git a/tests/Validation/ValidationExistsRuleTest.php b/tests/Validation/ValidationExistsRuleTest.php
index 3208b25156e8..d5cce447cfd0 100644
--- a/tests/Validation/ValidationExistsRuleTest.php
+++ b/tests/Validation/ValidationExistsRuleTest.php
@@ -58,6 +58,10 @@ public function testItCorrectlyFormatsAStringVersionOfTheRule()
         $rule = new Exists(NoTableNameModel::class, 'column');
         $rule->where('foo', 'bar');
         $this->assertSame('exists:no_table_name_models,column,foo,"bar"', (string) $rule);
+
+        $rule = new Exists(ClassWithRequiredConstructorParameters::class, 'column');
+        $rule->where('foo', 'bar');
+        $this->assertSame('exists:'.ClassWithRequiredConstructorParameters::class.',column,foo,"bar"', (string) $rule);
     }
 
     public function testItChoosesValidRecordsUsingWhereInRule()
@@ -203,3 +207,15 @@ class NoTableNameModel extends Eloquent
     protected $guarded = [];
     public $timestamps = false;
 }
+
+class ClassWithRequiredConstructorParameters
+{
+    private $bar;
+    private $baz;
+
+    public function __construct($bar, $baz)
+    {
+        $this->bar = $bar;
+        $this->baz = $baz;
+    }
+}
diff --git a/tests/Validation/ValidationUniqueRuleTest.php b/tests/Validation/ValidationUniqueRuleTest.php
index 46b591e4abce..c967ab7c077c 100644
--- a/tests/Validation/ValidationUniqueRuleTest.php
+++ b/tests/Validation/ValidationUniqueRuleTest.php
@@ -26,6 +26,10 @@ public function testItCorrectlyFormatsAStringVersionOfTheRule()
         $rule->where('foo', 'bar');
         $this->assertSame('unique:no_table_names,NULL,NULL,id,foo,"bar"', (string) $rule);
 
+        $rule = new Unique(ClassWithNonEmptyConstructor::class);
+        $rule->where('foo', 'bar');
+        $this->assertSame('unique:'.ClassWithNonEmptyConstructor::class.',NULL,NULL,id,foo,"bar"', (string) $rule);
+
         $rule = new Unique('table', 'column');
         $rule->ignore('Taylor, Otwell', 'id_column');
         $rule->where('foo', 'bar');
@@ -78,3 +82,15 @@ class NoTableName extends Model
     protected $guarded = [];
     public $timestamps = false;
 }
+
+class ClassWithNonEmptyConstructor
+{
+    private $bar;
+    private $baz;
+
+    public function __construct($bar, $baz)
+    {
+        $this->bar = $bar;
+        $this->baz = $baz;
+    }
+}