diff --git a/forms/OptionsetField.php b/forms/OptionsetField.php
index 5e2e36e12..010c9ff22 100644
--- a/forms/OptionsetField.php
+++ b/forms/OptionsetField.php
@@ -93,7 +93,7 @@ class OptionsetField extends DropdownField {
 	public function performReadonlyTransformation() {
 		// Source and values are DataObject sets.
 		$field = $this->castedCopy('LookupField');
-		$field->setValue($this->getSource());
+		$field->setSource($this->getSource());
 		$field->setReadonly(true);
 		
 		return $field;
diff --git a/tests/forms/OptionsetFieldTest.php b/tests/forms/OptionsetFieldTest.php
index 0bb4070d1..81d66fe77 100644
--- a/tests/forms/OptionsetFieldTest.php
+++ b/tests/forms/OptionsetFieldTest.php
@@ -24,4 +24,14 @@ class OptionsetFieldTest extends SapphireTest {
 			''
 		);
 	}
+
+	public function testReadonlyField() {
+		$sourceArray = array(0 => 'No', 1 => 'Yes');
+		$field = new OptionsetField('FeelingOk', 'are you feeling ok?', $sourceArray, 1);
+		$field->setEmptyString('(Select one)');
+		$field->setValue(1);
+		$readonlyField = $field->performReadonlyTransformation();
+		preg_match('/Yes/', $field->Field(), $matches);
+		$this->assertEquals($matches[0], 'Yes');
+	}
 }