diff --git a/llama-index-core/llama_index/core/base/query_pipeline/query.py b/llama-index-core/llama_index/core/base/query_pipeline/query.py
index 01f890e47bebb..fd5de0bd0e00e 100644
--- a/llama-index-core/llama_index/core/base/query_pipeline/query.py
+++ b/llama-index-core/llama_index/core/base/query_pipeline/query.py
@@ -16,6 +16,7 @@
 
 from llama_index.core.base.llms.types import (
     ChatResponse,
+    ChatMessage,
     CompletionResponse,
 )
 from llama_index.core.base.response.schema import Response
@@ -27,6 +28,7 @@
 StringableInput = Union[
     CompletionResponse,
     ChatResponse,
+    ChatMessage,
     str,
     QueryBundle,
     Response,
diff --git a/llama-index-core/tests/query_pipeline/test_utils.py b/llama-index-core/tests/query_pipeline/test_utils.py
new file mode 100644
index 0000000000000..8f4648905784d
--- /dev/null
+++ b/llama-index-core/tests/query_pipeline/test_utils.py
@@ -0,0 +1,8 @@
+from llama_index.core.base.llms.types import ChatMessage, MessageRole
+from llama_index.core.base.query_pipeline.query import validate_and_convert_stringable
+
+
+def test_validate_and_convert_stringable() -> None:
+    """Test conversion of stringable object into string."""
+    message = ChatMessage(role=MessageRole.USER, content="hello")
+    assert validate_and_convert_stringable(message) == "user: hello"