diff --git a/checkstyle/plugin.jelly b/checkstyle/plugin.jelly
index 0bee9dd4..4bcab851 100644
--- a/checkstyle/plugin.jelly
+++ b/checkstyle/plugin.jelly
@@ -48,6 +48,8 @@
       <ant:taskdef name="checkstyle"
         classname="com.puppycrawl.tools.checkstyle.CheckStyleTask">
         <ant:classpath>
+          <ant:pathelement location="${plugin.getDependencyPath('checkstyle:checkstyle')}"/>
+          <ant:pathelement location="${plugin.getDependencyPath('checkstyle:checkstyle-optional')}"/>
           <ant:pathelement location="${plugin.getDependencyPath('checkstyle:checkstyle')}"/>
           <ant:pathelement location="${plugin.getDependencyPath('antlr:antlr')}"/>
           <ant:pathelement location="${plugin.getDependencyPath('regexp:regexp')}"/>