diff --git a/runnercontext.cpp b/runnercontext.cpp
index f7a83d0ed..643a42275 100644
--- a/runnercontext.cpp
+++ b/runnercontext.cpp
@@ -208,7 +208,7 @@ QString RunnerContext::mimeType() const
     return d->mimeType;
 }
 
-bool RunnerContext::isValid()
+bool RunnerContext::isValid() const
 {
     // if our qptr is dirty, we aren't useful anymore
     return (d->q != &(d->s_dummyContext));
diff --git a/runnercontext.h b/runnercontext.h
index ab68fd0c6..7de05cc03 100644
--- a/runnercontext.h
+++ b/runnercontext.h
@@ -119,7 +119,7 @@ class PLASMA_EXPORT RunnerContext : public QObject
          * to avoid unecessary processing in runners that may run for an extended
          * period (as measured in 10s of ms) and therefore improve the user experience. @since 4.2.3
          */
-        bool isValid();
+        bool isValid() const;
 
 
          /**