diff --git a/src/crewai/task.py b/src/crewai/task.py
index 030bce779..c96d1aa5a 100644
--- a/src/crewai/task.py
+++ b/src/crewai/task.py
@@ -431,7 +431,9 @@ class Task(BaseModel):
             content = (
                 json_output
                 if json_output
-                else pydantic_output.model_dump_json() if pydantic_output else result
+                else pydantic_output.model_dump_json()
+                if pydantic_output
+                else result
             )
             self._save_file(content)
 
@@ -452,7 +454,7 @@ class Task(BaseModel):
         return "\n".join(tasks_slices)
 
     def interpolate_inputs_and_add_conversation_history(
-        self, inputs: Dict[str, Union[str, int, float]]
+        self, inputs: Dict[str, Union[str, int, float, dict, list]]
     ) -> None:
         """Interpolate inputs into the task description, expected output, and output file path.
            Add conversation history if present.
@@ -524,7 +526,9 @@ class Task(BaseModel):
             )
 
     def interpolate_only(
-        self, input_string: Optional[str], inputs: Dict[str, Union[str, int, float]]
+        self,
+        input_string: Optional[str],
+        inputs: Dict[str, Union[str, int, float, dict, list]],
     ) -> str:
         """Interpolate placeholders (e.g., {key}) in a string while leaving JSON untouched.
 
@@ -551,14 +555,16 @@ class Task(BaseModel):
             raise ValueError(
                 "Inputs dictionary cannot be empty when interpolating variables"
             )
-
         try:
             # Validate input types
             for key, value in inputs.items():
-                if not isinstance(value, (str, int, float)):
+                print("key", key, value)
+                if not isinstance(value, (str, int, float, dict, list)):
                     raise ValueError(
-                        f"Value for key '{key}' must be a string, integer, or float, got {type(value).__name__}"
+                        f"Value for key '{key}' must be a string, integer, float, dict, or list, got {type(value).__name__}"
                     )
+                if isinstance(value, (dict, list)):
+                    inputs[key] = json.dumps(value, ensure_ascii=False)
 
             escaped_string = input_string.replace("{", "{{").replace("}", "}}")
 
diff --git a/tests/task_test.py b/tests/task_test.py
index 59e58dcca..f31895e24 100644
--- a/tests/task_test.py
+++ b/tests/task_test.py
@@ -441,9 +441,9 @@ def test_output_pydantic_to_another_task():
     crew = Crew(agents=[scorer], tasks=[task1, task2], verbose=True)
     result = crew.kickoff()
     pydantic_result = result.pydantic
-    assert isinstance(
-        pydantic_result, ScoreOutput
-    ), "Expected pydantic result to be of type ScoreOutput"
+    assert isinstance(pydantic_result, ScoreOutput), (
+        "Expected pydantic result to be of type ScoreOutput"
+    )
     assert pydantic_result.score == 5
 
 
@@ -779,6 +779,43 @@ def test_interpolate_only():
     assert result == no_placeholders
 
 
+def test_interpolate_only_with_dict_inside_expected_output():
+    """Test the interpolate_only method for various scenarios including JSON structure preservation."""
+    task = Task(
+        description="Unused in this test",
+        expected_output="Unused in this test: {questions}",
+    )
+
+    json_string = '{"questions": {"main_question": "What is the user\'s name?", "secondary_question": "What is the user\'s age?"}}'
+    result = task.interpolate_only(
+        input_string=json_string,
+        inputs={
+            "questions": {
+                "main_question": "What is the user's name?",
+                "secondary_question": "What is the user's age?",
+            }
+        },
+    )
+    assert '"main_question": "What is the user\'s name?"' in result
+    assert '"secondary_question": "What is the user\'s age?"' in result
+    assert result == json_string
+
+    normal_string = "Hello {name}, welcome to {place}!"
+    result = task.interpolate_only(
+        input_string=normal_string, inputs={"name": "John", "place": "CrewAI"}
+    )
+    assert result == "Hello John, welcome to CrewAI!"
+
+    result = task.interpolate_only(input_string="", inputs={"unused": "value"})
+    assert result == ""
+
+    no_placeholders = "Hello, this is a test"
+    result = task.interpolate_only(
+        input_string=no_placeholders, inputs={"unused": "value"}
+    )
+    assert result == no_placeholders
+
+
 def test_task_output_str_with_pydantic():
     from crewai.tasks.output_format import OutputFormat
 
@@ -870,9 +907,9 @@ def test_key():
     assert task.key == hash, "The key should be the hash of the description."
 
     task.interpolate_inputs_and_add_conversation_history(inputs={"topic": "AI"})
-    assert (
-        task.key == hash
-    ), "The key should be the hash of the non-interpolated description."
+    assert task.key == hash, (
+        "The key should be the hash of the non-interpolated description."
+    )
 
 
 def test_output_file_validation():