diff --git a/src/pipeline.cc b/src/pipeline.cc
index 2a341782..864555b8 100644
--- a/src/pipeline.cc
+++ b/src/pipeline.cc
@@ -598,12 +598,19 @@ class PipelineWorker : public AsyncWorker {
           baton->background[2] * multiplier
         };
         // Add alpha channel to background colour
-        if (HasAlpha(image)) {
+        if (baton->background[3] < 255.0 || HasAlpha(image)) {
           background.push_back(baton->background[3] * multiplier);
         }
+        // Add non-transparent alpha channel, if required
+        if (baton->background[3] < 255.0 && !HasAlpha(image)) {
+          image = image.bandjoin(
+            VImage::new_matrix(image.width(), image.height()).new_from_image(255 * multiplier)
+          );
+        }
         // Embed
         baton->width = image.width() + baton->extendLeft + baton->extendRight;
         baton->height = image.height() + baton->extendTop + baton->extendBottom;
+
         image = image.embed(baton->extendLeft, baton->extendTop, baton->width, baton->height,
           VImage::option()->set("extend", VIPS_EXTEND_BACKGROUND)->set("background", background));
       }
diff --git a/test/fixtures/expected/addAlphaChanelBeforeExtend.png b/test/fixtures/expected/addAlphaChanelBeforeExtend.png
new file mode 100644
index 00000000..ebb7b0c4
Binary files /dev/null and b/test/fixtures/expected/addAlphaChanelBeforeExtend.png differ
diff --git a/test/unit/extend.js b/test/unit/extend.js
index 2232512d..ca48d350 100644
--- a/test/unit/extend.js
+++ b/test/unit/extend.js
@@ -49,4 +49,16 @@ describe('Extend', function () {
     });
   });
 
+  it('should add alpha channel before extending with a transparent Background', function( done ){
+    sharp(fixtures.inputJpgWithLandscapeExif1)
+      .background({r: 0, g: 0, b: 0, a: 0})
+      .toFormat( sharp.format.png )
+      .extend({top: 0, bottom: 10, left: 0, right: 10})
+      .toBuffer( function(err, data, info){
+        assert.strictEqual(610, info.width);
+        assert.strictEqual(460, info.height);
+        fixtures.assertSimilar(fixtures.expected('addAlphaChanelBeforeExtend.png'), data, done);
+      });
+  });
+
 });