diff --git a/RELEASENOTES.md b/RELEASENOTES.md
index 02807708b8..a7fc67516a 100644
--- a/RELEASENOTES.md
+++ b/RELEASENOTES.md
@@ -7,6 +7,9 @@
         implement playback resumption with media button events sent by, for
         example, a Bluetooth headset
         ([#167](https://github.com/androidx/media/issues/167)).
+    *   Fix bug where a combined `Timeline` and position update in a
+        `MediaSession` may cause a `MediaController` to throw an
+        `IllegalStateException`.
 *   Remove deprecated symbols:
     *   Remove two deprecated `SimpleCache` constructors, use a non-deprecated
         constructor that takes a `DatabaseProvider` instead for better
diff --git a/libraries/session/src/main/java/androidx/media3/session/MediaControllerImplBase.java b/libraries/session/src/main/java/androidx/media3/session/MediaControllerImplBase.java
index f1128e8969..5a4b33be2b 100644
--- a/libraries/session/src/main/java/androidx/media3/session/MediaControllerImplBase.java
+++ b/libraries/session/src/main/java/androidx/media3/session/MediaControllerImplBase.java
@@ -2613,6 +2613,13 @@ public void onRenderedFirstFrame() {
   private void updateSessionPositionInfoIfNeeded(SessionPositionInfo sessionPositionInfo) {
     if (pendingMaskingSequencedFutureNumbers.isEmpty()
         && playerInfo.sessionPositionInfo.eventTimeMs < sessionPositionInfo.eventTimeMs) {
+      if (!MediaUtils.areSessionPositionInfosInSamePeriodOrAd(
+          sessionPositionInfo, playerInfo.sessionPositionInfo)) {
+        // MediaSessionImpl before version 1.0.2 has a bug that may send position info updates for
+        // new periods too early. Ignore these updates to avoid an inconsistent state (see
+        // [internal b/277301159]).
+        return;
+      }
       playerInfo = playerInfo.copyWithSessionPositionInfo(sessionPositionInfo);
     }
   }
diff --git a/libraries/session/src/main/java/androidx/media3/session/MediaSessionImpl.java b/libraries/session/src/main/java/androidx/media3/session/MediaSessionImpl.java
index db50614290..74d660bbf7 100644
--- a/libraries/session/src/main/java/androidx/media3/session/MediaSessionImpl.java
+++ b/libraries/session/src/main/java/androidx/media3/session/MediaSessionImpl.java
@@ -807,7 +807,16 @@ private void notifyPeriodicSessionPositionInfoChangesOnHandler() {
       }
     }
     SessionPositionInfo sessionPositionInfo = playerWrapper.createSessionPositionInfoForBundling();
-    dispatchOnPeriodicSessionPositionInfoChanged(sessionPositionInfo);
+    if (!onPlayerInfoChangedHandler.hasPendingPlayerInfoChangedUpdate()
+        && MediaUtils.areSessionPositionInfosInSamePeriodOrAd(
+            sessionPositionInfo, playerInfo.sessionPositionInfo)) {
+      // Send a periodic position info only if a PlayerInfo update is not already already pending
+      // and the player state is still corresponding to the currently known PlayerInfo. Both
+      // conditions will soon trigger a new PlayerInfo update with the latest position info anyway
+      // and we also don't want to send a new position info early if the corresponding Timeline
+      // update hasn't been sent yet (see [internal b/277301159]).
+      dispatchOnPeriodicSessionPositionInfoChanged(sessionPositionInfo);
+    }
     schedulePeriodicSessionPositionInfoChanges();
   }
 
@@ -1362,11 +1371,15 @@ public void handleMessage(Message msg) {
       }
     }
 
+    public boolean hasPendingPlayerInfoChangedUpdate() {
+      return hasMessages(MSG_PLAYER_INFO_CHANGED);
+    }
+
     public void sendPlayerInfoChangedMessage(boolean excludeTimeline, boolean excludeTracks) {
       this.excludeTimeline = this.excludeTimeline && excludeTimeline;
       this.excludeTracks = this.excludeTracks && excludeTracks;
-      if (!onPlayerInfoChangedHandler.hasMessages(MSG_PLAYER_INFO_CHANGED)) {
-        onPlayerInfoChangedHandler.sendEmptyMessage(MSG_PLAYER_INFO_CHANGED);
+      if (!hasMessages(MSG_PLAYER_INFO_CHANGED)) {
+        sendEmptyMessage(MSG_PLAYER_INFO_CHANGED);
       }
     }
   }
diff --git a/libraries/session/src/main/java/androidx/media3/session/MediaUtils.java b/libraries/session/src/main/java/androidx/media3/session/MediaUtils.java
index 0fda511e7c..a15d5fe0c3 100644
--- a/libraries/session/src/main/java/androidx/media3/session/MediaUtils.java
+++ b/libraries/session/src/main/java/androidx/media3/session/MediaUtils.java
@@ -1476,6 +1476,19 @@ public static void setMediaItemsWithStartIndexAndPosition(
     }
   }
 
+  /**
+   * Returns whether the two provided {@link SessionPositionInfo} describe a position in the same
+   * period or ad.
+   */
+  public static boolean areSessionPositionInfosInSamePeriodOrAd(
+      SessionPositionInfo info1, SessionPositionInfo info2) {
+    // TODO: b/259220235 - Use UIDs instead of mediaItemIndex and periodIndex
+    return info1.positionInfo.mediaItemIndex == info2.positionInfo.mediaItemIndex
+        && info1.positionInfo.periodIndex == info2.positionInfo.periodIndex
+        && info1.positionInfo.adGroupIndex == info2.positionInfo.adGroupIndex
+        && info1.positionInfo.adIndexInAdGroup == info2.positionInfo.adIndexInAdGroup;
+  }
+
   private static byte[] convertToByteArray(Bitmap bitmap) throws IOException {
     try (ByteArrayOutputStream stream = new ByteArrayOutputStream()) {
       bitmap.compress(Bitmap.CompressFormat.PNG, /* ignored */ 0, stream);
diff --git a/libraries/test_session_current/src/androidTest/java/androidx/media3/session/MediaControllerTest.java b/libraries/test_session_current/src/androidTest/java/androidx/media3/session/MediaControllerTest.java
index 4a4c01db4f..5405c0f6d7 100644
--- a/libraries/test_session_current/src/androidTest/java/androidx/media3/session/MediaControllerTest.java
+++ b/libraries/test_session_current/src/androidTest/java/androidx/media3/session/MediaControllerTest.java
@@ -34,6 +34,7 @@
 import android.content.Context;
 import android.os.Bundle;
 import android.os.RemoteException;
+import androidx.annotation.Nullable;
 import androidx.media3.common.AudioAttributes;
 import androidx.media3.common.C;
 import androidx.media3.common.Format;
@@ -1064,6 +1065,51 @@ public void getBufferedPosition_whilePausedAndNotLoading_isNotUpdatedPeriodicall
     assertThat(bufferedPositionAfterDelay.get()).isNotEqualTo(testBufferedPosition);
   }
 
+  @Test
+  public void
+      getCurrentMediaItemIndex_withPeriodicUpdateOverlappingTimelineChanges_updatesIndexCorrectly()
+          throws Exception {
+    Bundle playerConfig =
+        new RemoteMediaSession.MockPlayerConfigBuilder()
+            .setPlayWhenReady(true)
+            .setPlaybackState(Player.STATE_READY)
+            .build();
+    remoteSession.setPlayer(playerConfig);
+    MediaController controller = controllerTestRule.createController(remoteSession.getToken());
+    ArrayList<Integer> transitionMediaItemIndices = new ArrayList<>();
+    controller.addListener(
+        new Player.Listener() {
+          @Override
+          public void onMediaItemTransition(@Nullable MediaItem mediaItem, int reason) {
+            transitionMediaItemIndices.add(controller.getCurrentMediaItemIndex());
+          }
+        });
+
+    // Intentionally trigger update often to ensure there is a likely overlap with Timeline updates.
+    remoteSession.setSessionPositionUpdateDelayMs(1L);
+    // Trigger many timeline and position updates that are incompatible with any previous updates.
+    for (int i = 1; i <= 100; i++) {
+      remoteSession.getMockPlayer().createAndSetFakeTimeline(/* windowCount= */ i);
+      remoteSession.getMockPlayer().setCurrentMediaItemIndex(i - 1);
+      remoteSession
+          .getMockPlayer()
+          .notifyTimelineChanged(Player.TIMELINE_CHANGE_REASON_PLAYLIST_CHANGED);
+      remoteSession
+          .getMockPlayer()
+          .notifyMediaItemTransition(
+              /* index= */ i - 1, Player.MEDIA_ITEM_TRANSITION_REASON_PLAYLIST_CHANGED);
+    }
+    PollingCheck.waitFor(TIMEOUT_MS, () -> transitionMediaItemIndices.size() == 100);
+
+    ImmutableList.Builder<Integer> expectedMediaItemIndices = ImmutableList.builder();
+    for (int i = 0; i < 100; i++) {
+      expectedMediaItemIndices.add(i);
+    }
+    assertThat(transitionMediaItemIndices)
+        .containsExactlyElementsIn(expectedMediaItemIndices.build())
+        .inOrder();
+  }
+
   @Test
   public void getContentBufferedPosition_byDefault_returnsZero() throws Exception {
     MediaController controller = controllerTestRule.createController(remoteSession.getToken());