diff --git a/vcl/source/outdev/bitmap.cxx b/vcl/source/outdev/bitmap.cxx
index 92b9214e26df..3c91094fa025 100644
--- a/vcl/source/outdev/bitmap.cxx
+++ b/vcl/source/outdev/bitmap.cxx
@@ -428,7 +428,7 @@ BitmapColor lcl_AlphaBlend(int nX, int nY,
                                BitmapReadAccess const* pSrcAlphaBmp,
                                BitmapReadAccess const* pDstBmp)
 {
-    BitmapColor aSrcCol = pSrcBmp->GetColor(nMapY, nMapX);
+    const BitmapColor aSrcCol = pSrcBmp->GetColor(nMapY, nMapX);
     BitmapColor aDstCol = pDstBmp->GetColor(nY, nX);
 
     const sal_uInt8 nSrcAlpha = pSrcAlphaBmp->GetPixelIndex(nMapY, nMapX);