diff --git a/homeassistant/helpers/entity_platform.py b/homeassistant/helpers/entity_platform.py
index d101abe2b1a..fb542f660d1 100644
--- a/homeassistant/helpers/entity_platform.py
+++ b/homeassistant/helpers/entity_platform.py
@@ -325,11 +325,13 @@ class EntityPlatform:
                 entity.platform = None
                 return
 
+        requested_entity_id = None
         suggested_object_id = None
 
         # Get entity_id from unique ID registration
         if entity.unique_id is not None:
             if entity.entity_id is not None:
+                requested_entity_id = entity.entity_id
                 suggested_object_id = split_entity_id(entity.entity_id)[1]
             else:
                 suggested_object_id = entity.name
@@ -435,9 +437,14 @@ class EntityPlatform:
                 already_exists = True
 
         if already_exists:
-            msg = f"Entity id already exists - ignoring: {entity.entity_id}"
             if entity.unique_id is not None:
-                msg += f". Platform {self.platform_name} does not generate unique IDs"
+                msg = f"Platform {self.platform_name} does not generate unique IDs. "
+                if requested_entity_id:
+                    msg += f"ID {entity.unique_id} is already used by {entity.entity_id} - ignoring {requested_entity_id}"
+                else:
+                    msg += f"ID {entity.unique_id} already exists - ignoring {entity.entity_id}"
+            else:
+                msg = f"Entity id already exists - ignoring: {entity.entity_id}"
             self.logger.error(msg)
             entity.hass = None
             entity.platform = None
diff --git a/tests/helpers/test_entity_platform.py b/tests/helpers/test_entity_platform.py
index ddecd1988ed..527a89843dd 100644
--- a/tests/helpers/test_entity_platform.py
+++ b/tests/helpers/test_entity_platform.py
@@ -375,8 +375,9 @@ async def test_async_remove_with_platform(hass):
     assert len(hass.states.async_entity_ids()) == 0
 
 
-async def test_not_adding_duplicate_entities_with_unique_id(hass):
+async def test_not_adding_duplicate_entities_with_unique_id(hass, caplog):
     """Test for not adding duplicate entities."""
+    caplog.set_level(logging.ERROR)
     component = EntityComponent(_LOGGER, DOMAIN, hass)
 
     await component.async_add_entities(
@@ -384,9 +385,20 @@ async def test_not_adding_duplicate_entities_with_unique_id(hass):
     )
 
     assert len(hass.states.async_entity_ids()) == 1
+    assert not caplog.text
 
     ent2 = MockEntity(name="test2", unique_id="not_very_unique")
     await component.async_add_entities([ent2])
+    assert "test1" in caplog.text
+    assert DOMAIN in caplog.text
+
+    ent3 = MockEntity(
+        name="test2", entity_id="test_domain.test3", unique_id="not_very_unique"
+    )
+    await component.async_add_entities([ent3])
+    assert "test1" in caplog.text
+    assert "test3" in caplog.text
+    assert DOMAIN in caplog.text
 
     assert ent2.hass is None
     assert ent2.platform is None