diff --git a/includes/page/CategoryPage.php b/includes/page/CategoryPage.php
index 7dea27113dd..2d7e8f24fda 100644
--- a/includes/page/CategoryPage.php
+++ b/includes/page/CategoryPage.php
@@ -27,7 +27,7 @@
  */
 class CategoryPage extends Article {
 	# Subclasses can change this to override the viewer class.
-	public $mCategoryViewerClass = 'CategoryViewer';
+	protected $mCategoryViewerClass = 'CategoryViewer';
 
 	/**
 	 * @var WikiCategoryPage
@@ -117,4 +117,12 @@ class CategoryPage extends Article {
 		$out->addHTML( $viewer->getHTML() );
 		$this->addHelpLink( 'Help:Categories' );
 	}
+
+	function getCategoryViewerClass() {
+		return $this->mCategoryViewerClass;
+	}
+
+	function setCategoryViewerClass( $class ) {
+		$this->mCategoryViewerClass = $class;
+	}
 }