diff --git a/hwc2_device/HwcLayer.h b/hwc2_device/HwcLayer.h
index 953e589..6b234f7 100644
--- a/hwc2_device/HwcLayer.h
+++ b/hwc2_device/HwcLayer.h
@@ -35,6 +35,7 @@
     std::optional<BufferSampleRange> sample_range;
     std::optional<HWC2::Composition> composition_type;
     std::optional<hwc_rect_t> display_frame;
+    std::optional<float> alpha;
   };
 
   explicit HwcLayer(HwcDisplay *parent_display) : parent_(parent_display){};