diff --git a/tests/test_message.py b/tests/test_message.py
index 91e89f9..6a7fc56 100644
--- a/tests/test_message.py
+++ b/tests/test_message.py
@@ -23,7 +23,7 @@ def test_message(message_data: dict):
     assert message.model_dump() == message_data
 
 
-@pytest.mark.parametrize("field", ["role", "content", "timestamp"])
+@pytest.mark.parametrize("field", ["role", "content"])
 def test_message_raise_missing(message_data: dict, field: str):
     """
     Test that Message object raises an error when missing a required field.
diff --git a/uncertainty_engine_types/message.py b/uncertainty_engine_types/message.py
index 3550961..8cab135 100644
--- a/uncertainty_engine_types/message.py
+++ b/uncertainty_engine_types/message.py
@@ -1,13 +1,13 @@
 from datetime import datetime
 from typing import Any, Literal
 
-from pydantic import BaseModel, field_validator
+from pydantic import BaseModel, field_validator, Field
 
 
 class Message(BaseModel):
     role: Literal["instruction", "user", "engine"]
     content: str
-    timestamp: datetime
+    timestamp: datetime = Field(default_factory=datetime.now)
 
     @field_validator("content", mode="before")
     @classmethod