diff --git a/demos/composition/src/main/java/androidx/media3/demo/composition/CompositionPreviewActivity.java b/demos/composition/src/main/java/androidx/media3/demo/composition/CompositionPreviewActivity.java
index 36a4ade823..edf1f4a1ea 100644
--- a/demos/composition/src/main/java/androidx/media3/demo/composition/CompositionPreviewActivity.java
+++ b/demos/composition/src/main/java/androidx/media3/demo/composition/CompositionPreviewActivity.java
@@ -23,6 +23,7 @@ import androidx.annotation.Nullable;
 import androidx.appcompat.app.AlertDialog;
 import androidx.appcompat.app.AppCompatActivity;
 import androidx.appcompat.widget.AppCompatButton;
+import androidx.appcompat.widget.AppCompatCheckBox;
 import androidx.appcompat.widget.AppCompatTextView;
 import androidx.media3.common.Effect;
 import androidx.media3.common.MediaItem;
@@ -63,6 +64,8 @@ import org.json.JSONObject;
  */
 public final class CompositionPreviewActivity extends AppCompatActivity {
   private static final String TAG = "CompPreviewActivity";
+  private static final String AUDIO_URI =
+      "https://storage.googleapis.com/exoplayer-test-media-0/play.mp3";
 
   private ArrayList<String> sequenceAssetTitles;
   private boolean[] selectedMediaItems;
@@ -75,6 +78,7 @@ public final class CompositionPreviewActivity extends AppCompatActivity {
   private AppCompatButton exportButton;
   private AppCompatTextView exportInformationTextView;
   private Stopwatch exportStopwatch;
+  private boolean includeBackgroundAudioTrack;
 
   @Override
   protected void onCreate(@Nullable Bundle savedInstanceState) {
@@ -94,6 +98,10 @@ public final class CompositionPreviewActivity extends AppCompatActivity {
     exportButton = findViewById(R.id.composition_export_button);
     exportButton.setOnClickListener(view -> exportComposition());
 
+    AppCompatCheckBox backgroundAudioCheckBox = findViewById(R.id.background_audio_checkbox);
+    backgroundAudioCheckBox.setOnCheckedChangeListener(
+        (compoundButton, checked) -> includeBackgroundAudioTrack = checked);
+
     presetDescriptions = getResources().getStringArray(R.array.preset_descriptions);
     // Select two media items by default.
     selectedMediaItems = new boolean[presetDescriptions.length];
@@ -140,6 +148,9 @@ public final class CompositionPreviewActivity extends AppCompatActivity {
     ImmutableList<Effect> effects =
         ImmutableList.of(
             MatrixTransformationFactory.createDizzyCropEffect(), RgbFilter.createGrayscaleFilter());
+    // Preview requires all sequences to be the same duration, so calculate main sequence duration
+    // and limit background sequence duration to match.
+    long videoSequenceDurationUs = 0;
     for (int i = 0; i < selectedMediaItems.length; i++) {
       if (selectedMediaItems[i]) {
         SonicAudioProcessor pitchChanger = new SonicAudioProcessor();
@@ -156,13 +167,19 @@ public final class CompositionPreviewActivity extends AppCompatActivity {
                         /* audioProcessors= */ ImmutableList.of(pitchChanger),
                         /* videoEffects= */ effects))
                 .setDurationUs(presetDurationsUs[i]);
+        videoSequenceDurationUs += presetDurationsUs[i];
         mediaItems.add(itemBuilder.build());
       }
     }
     EditedMediaItemSequence videoSequence = new EditedMediaItemSequence(mediaItems);
+    List<EditedMediaItemSequence> compositionSequences = new ArrayList<>();
+    compositionSequences.add(videoSequence);
+    if (includeBackgroundAudioTrack) {
+      compositionSequences.add(getAudioBackgroundSequence(Util.usToMs(videoSequenceDurationUs)));
+    }
     SonicAudioProcessor sampleRateChanger = new SonicAudioProcessor();
     sampleRateChanger.setOutputSampleRateHz(8_000);
-    return new Composition.Builder(/* sequences= */ ImmutableList.of(videoSequence))
+    return new Composition.Builder(/* sequences= */ compositionSequences)
         .setEffects(
             new Effects(
                 /* audioProcessors= */ ImmutableList.of(sampleRateChanger),
@@ -170,6 +187,21 @@ public final class CompositionPreviewActivity extends AppCompatActivity {
         .build();
   }
 
+  private EditedMediaItemSequence getAudioBackgroundSequence(long durationMs) {
+    MediaItem audioMediaItem =
+        new MediaItem.Builder()
+            .setUri(AUDIO_URI)
+            .setClippingConfiguration(
+                new MediaItem.ClippingConfiguration.Builder()
+                    .setStartPositionMs(0)
+                    .setEndPositionMs(durationMs)
+                    .build())
+            .build();
+    EditedMediaItem audioItem =
+        new EditedMediaItem.Builder(audioMediaItem).setDurationUs(59_000_000).build();
+    return new EditedMediaItemSequence(audioItem);
+  }
+
   private void previewComposition() {
     releasePlayer();
     Composition composition = prepareComposition();
diff --git a/demos/composition/src/main/res/layout/composition_preview_activity.xml b/demos/composition/src/main/res/layout/composition_preview_activity.xml
index 83819ec920..185565b2d9 100644
--- a/demos/composition/src/main/res/layout/composition_preview_activity.xml
+++ b/demos/composition/src/main/res/layout/composition_preview_activity.xml
@@ -92,7 +92,16 @@
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
     app:layout_constraintStart_toStartOf="parent"
-    app:layout_constraintBottom_toTopOf="@id/composition_export_button"/>
+    app:layout_constraintBottom_toTopOf="@id/background_audio_checkbox"/>
+
+  <androidx.appcompat.widget.AppCompatCheckBox
+    android:id="@+id/background_audio_checkbox"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:text="@string/add_background_audio"
+    app:layout_constraintStart_toStartOf="parent"
+    app:layout_constraintEnd_toEndOf="parent"
+    app:layout_constraintBottom_toTopOf="@id/preview_button" />
 
   <androidx.appcompat.widget.AppCompatButton
     android:id="@+id/composition_export_button"
@@ -100,9 +109,9 @@
     android:layout_marginTop="16dp"
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
-    app:layout_constraintStart_toStartOf="parent"
+    app:layout_constraintStart_toEndOf="@id/preview_button"
     app:layout_constraintEnd_toEndOf="parent"
-    app:layout_constraintBottom_toTopOf="@id/preview_button"/>
+    app:layout_constraintBottom_toBottomOf="parent"/>
 
   <androidx.appcompat.widget.AppCompatButton
     android:id="@+id/preview_button"
@@ -111,7 +120,7 @@
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     app:layout_constraintStart_toStartOf="parent"
-    app:layout_constraintEnd_toEndOf="parent"
+    app:layout_constraintEnd_toStartOf="@id/composition_export_button"
     app:layout_constraintBottom_toBottomOf="parent"/>
 
 </androidx.constraintlayout.widget.ConstraintLayout>
diff --git a/demos/composition/src/main/res/values/strings.xml b/demos/composition/src/main/res/values/strings.xml
index b31465ffc0..bff981a978 100644
--- a/demos/composition/src/main/res/values/strings.xml
+++ b/demos/composition/src/main/res/values/strings.xml
@@ -24,4 +24,5 @@
   <string name="export_completed" translatable="false">Export completed in %.3f seconds.\nOutput: %s</string>
   <string name="export_error" translatable="false">Export error</string>
   <string name="export_started" translatable="false">Export started</string>
+  <string name="add_background_audio" translatable="false">Add background audio</string>
 </resources>