diff --git a/src/Symfony/Component/Form/FormBuilder.php b/src/Symfony/Component/Form/FormBuilder.php
index 51fc2cbe9d..be04e66bc3 100644
--- a/src/Symfony/Component/Form/FormBuilder.php
+++ b/src/Symfony/Component/Form/FormBuilder.php
@@ -144,7 +144,7 @@ class FormBuilder extends FormConfig implements \IteratorAggregate, FormBuilderI
     {
         unset($this->unresolvedChildren[$name]);
 
-        if (isset($this->children[$name])) {
+        if (array_key_exists($name, $this->children)) {
             if ($this->children[$name] instanceof self) {
                 $this->children[$name]->setParent(null);
             }
diff --git a/src/Symfony/Component/Form/Tests/FormBuilderTest.php b/src/Symfony/Component/Form/Tests/FormBuilderTest.php
index 52dcebc46f..42d4317459 100644
--- a/src/Symfony/Component/Form/Tests/FormBuilderTest.php
+++ b/src/Symfony/Component/Form/Tests/FormBuilderTest.php
@@ -134,6 +134,15 @@ class FormBuilderTest extends \PHPUnit_Framework_TestCase
         $this->assertFalse($this->builder->has('foo'));
     }
 
+    // https://github.com/symfony/symfony/pull/4826
+    public function testRemoveAndGetForm()
+    {
+        $this->builder->add('foo', 'text');
+        $this->builder->remove('foo');
+        $form = $this->builder->getForm();
+        $this->assertInstanceOf('Symfony\Component\Form\Form', $form);
+    }
+
     public function testCreateNoTypeNo()
     {
         $this->factory->expects($this->once())