diff --git a/src/corelib/thread/qrunnable.cpp b/src/corelib/thread/qrunnable.cpp
index 5418fc8ecf..bcb19d7af4 100644
--- a/src/corelib/thread/qrunnable.cpp
+++ b/src/corelib/thread/qrunnable.cpp
@@ -21,6 +21,17 @@ QRunnable *QRunnable::warnNullCallable()
     return nullptr;
 }
 
+
+QRunnable::QGenericRunnable::~QGenericRunnable()
+{
+    runHelper->destroy();
+}
+
+void QRunnable::QGenericRunnable::run()
+{
+    runHelper->run();
+}
+
 /*!
     \class QRunnable
     \inmodule QtCore
diff --git a/src/corelib/thread/qrunnable.h b/src/corelib/thread/qrunnable.h
index 853228200f..f0dd0a582e 100644
--- a/src/corelib/thread/qrunnable.h
+++ b/src/corelib/thread/qrunnable.h
@@ -42,7 +42,7 @@ private:
     class QGenericRunnable;
 };
 
-class QRunnable::QGenericRunnable : public QRunnable
+class Q_CORE_EXPORT QRunnable::QGenericRunnable : public QRunnable
 {
     // Type erasure, to only instantiate a non-virtual class per Callable:
     class HelperBase
@@ -91,14 +91,9 @@ public:
         : runHelper(new Helper<std::decay_t<Callable>>(std::forward<Callable>(c)))
     {
     }
-    ~QGenericRunnable() override
-    {
-        runHelper->destroy();
-    }
-    void run() override
-    {
-        runHelper->run();
-    }
+    ~QGenericRunnable() override;
+
+    void run() override;
 };
 
 namespace QtPrivate {