--- a/mobile/android/base/java/org/mozilla/gecko/home/HomeConfig.java
+++ b/mobile/android/base/java/org/mozilla/gecko/home/HomeConfig.java
@@ -1598,17 +1598,17 @@ public final class HomeConfig {
     }
 
     // UUIDs used to create PanelConfigs for default built-in panels. These are
     // public because they can be used in "about:home?panel=UUID" query strings
     // to open specific panels without querying the active Home Panel
     // configuration. Because they don't consider the active configuration, it
     // is only sensible to do this for built-in panels (and not for dynamic
     // panels).
-    private static final String TOP_SITES_PANEL_ID = "4becc86b-41eb-429a-a042-88fe8b5a094e";
+    /* package-private */ static final String TOP_SITES_PANEL_ID = "4becc86b-41eb-429a-a042-88fe8b5a094e";
     private static final String BOOKMARKS_PANEL_ID = "7f6d419a-cd6c-4e34-b26f-f68b1b551907";
     private static final String HISTORY_PANEL_ID = "f134bf20-11f7-4867-ab8b-e8e705d7fbe8";
     private static final String COMBINED_HISTORY_PANEL_ID = "4d716ce2-e063-486d-9e7c-b190d7b04dc6";
     private static final String RECENT_TABS_PANEL_ID = "5c2601a5-eedc-4477-b297-ce4cef52adf8";
     private static final String REMOTE_TABS_PANEL_ID = "72429afd-8d8b-43d8-9189-14b779c563d0";
     private static final String DEPRECATED_READING_LIST_PANEL_ID = "20f4549a-64ad-4c32-93e4-1dcef792733b";
 
     private final HomeConfigBackend mBackend;

--- a/mobile/android/base/java/org/mozilla/gecko/home/HomePager.java
+++ b/mobile/android/base/java/org/mozilla/gecko/home/HomePager.java
@@ -8,16 +8,17 @@ package org.mozilla.gecko.home;
 import java.util.ArrayList;
 import java.util.EnumSet;
 import java.util.List;
 
 import org.mozilla.gecko.AppConstants.Versions;
 import org.mozilla.gecko.R;
 import org.mozilla.gecko.Telemetry;
 import org.mozilla.gecko.TelemetryContract;
+import org.mozilla.gecko.activitystream.ActivityStream;
 import org.mozilla.gecko.animation.PropertyAnimator;
 import org.mozilla.gecko.animation.ViewHelper;
 import org.mozilla.gecko.home.HomeAdapter.OnAddPanelListener;
 import org.mozilla.gecko.home.HomeConfig.PanelConfig;
 import org.mozilla.gecko.util.ThreadUtils;
 
 import android.content.Context;
 import android.graphics.Rect;
@@ -554,17 +555,27 @@ public class HomePager extends ViewPager
      *
      * @param panelId of panel to start a session for
      */
     private void startNewPanelTelemetrySession(String panelId) {
         // Stop the current panel's session if we have one.
         stopCurrentPanelTelemetrySession();
 
         mCurrentPanelSession = TelemetryContract.Session.HOME_PANEL;
-        mCurrentPanelSessionSuffix = panelId;
+
+        if (HomeConfig.TOP_SITES_PANEL_ID.equals(panelId) &&
+                ActivityStream.isEnabled(getContext())) {
+            // Override the panel ID for Activity Stream: we're reusing the topsites panel to show
+            // Activity Stream, i.e. AS ends up havin the same panel ID. We override this for telemetry
+            // to distinguish between topsites and AS:
+            mCurrentPanelSessionSuffix = "activity_stream";
+        } else {
+            mCurrentPanelSessionSuffix = panelId;
+        }
+
         Telemetry.startUISession(mCurrentPanelSession, mCurrentPanelSessionSuffix);
     }
 
     /**
      * Stop the current panel telemetry session if one exists.
      */
     private void stopCurrentPanelTelemetrySession() {
         if (mCurrentPanelSession != null) {