diff --git a/src/gui/image/qpixmap.cpp b/src/gui/image/qpixmap.cpp
index fb62889e40..0c8ab527b2 100644
--- a/src/gui/image/qpixmap.cpp
+++ b/src/gui/image/qpixmap.cpp
@@ -481,7 +481,7 @@ QMatrix QPixmap::trueMatrix(const QMatrix &m, int w, int h)
 
 bool QPixmap::isQBitmap() const
 {
-    return data->type == QPlatformPixmap::BitmapType;
+    return data && data->type == QPlatformPixmap::BitmapType;
 }
 
 /*!
diff --git a/tests/auto/gui/image/qpixmap/tst_qpixmap.cpp b/tests/auto/gui/image/qpixmap/tst_qpixmap.cpp
index 67d7e57fd4..4ffe357d09 100644
--- a/tests/auto/gui/image/qpixmap/tst_qpixmap.cpp
+++ b/tests/auto/gui/image/qpixmap/tst_qpixmap.cpp
@@ -105,6 +105,7 @@ private slots:
     void drawBitmap();
     void isNull();
     void task_246446();
+    void task_51271();
 
     void convertFromImageNoDetach();
     void convertFromImageDetach();
@@ -1441,6 +1442,14 @@ void tst_QPixmap::task_246446()
     QVERIFY(pm.mask().isNull());
 }
 
+void tst_QPixmap::task_51271()
+{
+    QPixmap pm;
+    QBitmap bm;
+    QVERIFY(!pm.isQBitmap()); // Should not crash !
+    QVERIFY(bm.isQBitmap());
+}
+
 void tst_QPixmap::preserveDepth()
 {
     QPixmap target(64, 64);