diff --git a/src/plugins/platforms/offscreen/qoffscreenwindow.cpp b/src/plugins/platforms/offscreen/qoffscreenwindow.cpp
index 1a1471c6874..683a2d04dde 100644
--- a/src/plugins/platforms/offscreen/qoffscreenwindow.cpp
+++ b/src/plugins/platforms/offscreen/qoffscreenwindow.cpp
@@ -130,6 +130,11 @@ WId QOffscreenWindow::winId() const
     return m_winId;
 }
 
+QSurfaceFormat QOffscreenWindow::format() const
+{
+    return window()->requestedFormat();
+}
+
 QMargins QOffscreenWindow::frameMargins() const
 {
     return m_margins;
diff --git a/src/plugins/platforms/offscreen/qoffscreenwindow.h b/src/plugins/platforms/offscreen/qoffscreenwindow.h
index d525f2c6578..419eabbc02f 100644
--- a/src/plugins/platforms/offscreen/qoffscreenwindow.h
+++ b/src/plugins/platforms/offscreen/qoffscreenwindow.h
@@ -26,6 +26,7 @@ public:
     void requestActivateWindow() override;
 
     WId winId() const override;
+    QSurfaceFormat format() const override;
 
     static QOffscreenWindow *windowForWinId(WId id);