diff --git a/src/crewai/crew.py b/src/crewai/crew.py
index d488783ea..d13c59b6e 100644
--- a/src/crewai/crew.py
+++ b/src/crewai/crew.py
@@ -1076,18 +1076,36 @@ class Crew(BaseModel):
         self,
         n_iterations: int,
         openai_model_name: Optional[str] = None,
+        llm: Optional[Union[str, LLM]] = None,
         inputs: Optional[Dict[str, Any]] = None,
     ) -> None:
-        """Test and evaluate the Crew with the given inputs for n iterations concurrently using concurrent.futures."""
+        """Test and evaluate the Crew with the given inputs for n iterations concurrently using concurrent.futures.
+        
+        Args:
+            n_iterations: Number of test iterations to run
+            openai_model_name: (Deprecated) OpenAI model name for backward compatibility
+            llm: LLM instance or model name to use for evaluation
+            inputs: Optional inputs for the crew
+        """
         test_crew = self.copy()
+        
+        # Convert string to LLM instance if needed
+        if isinstance(llm, str):
+            llm = LLM(model=llm)
+        
+        # Maintain backward compatibility
+        if openai_model_name and not llm:
+            llm = LLM(model=openai_model_name)
+        elif not llm:
+            raise ValueError("Either llm or openai_model_name must be provided")
 
         self._test_execution_span = test_crew._telemetry.test_execution_span(
             test_crew,
             n_iterations,
             inputs,
-            openai_model_name,  # type: ignore[arg-type]
-        )  # type: ignore[arg-type]
-        evaluator = CrewEvaluator(test_crew, openai_model_name)  # type: ignore[arg-type]
+            getattr(llm, "model", None),
+        )
+        evaluator = CrewEvaluator(test_crew, llm)
 
         for i in range(1, n_iterations + 1):
             evaluator.set_iteration(i)
diff --git a/src/crewai/utilities/evaluators/crew_evaluator_handler.py b/src/crewai/utilities/evaluators/crew_evaluator_handler.py
index 3387d91b3..e01a8a6c3 100644
--- a/src/crewai/utilities/evaluators/crew_evaluator_handler.py
+++ b/src/crewai/utilities/evaluators/crew_evaluator_handler.py
@@ -1,4 +1,5 @@
 from collections import defaultdict
+from typing import Union
 
 from pydantic import BaseModel, Field
 from rich.box import HEAVY_EDGE
@@ -6,6 +7,7 @@ from rich.console import Console
 from rich.table import Table
 
 from crewai.agent import Agent
+from crewai.llm import LLM
 from crewai.task import Task
 from crewai.tasks.task_output import TaskOutput
 from crewai.telemetry import Telemetry
@@ -32,9 +34,9 @@ class CrewEvaluator:
     run_execution_times: defaultdict = defaultdict(list)
     iteration: int = 0
 
-    def __init__(self, crew, openai_model_name: str):
+    def __init__(self, crew, llm: Union[str, LLM]):
         self.crew = crew
-        self.openai_model_name = openai_model_name
+        self.llm = llm if isinstance(llm, LLM) else LLM(model=llm)
         self._telemetry = Telemetry()
         self._setup_for_evaluating()
 
@@ -51,7 +53,7 @@ class CrewEvaluator:
             ),
             backstory="Evaluator agent for crew evaluation with precise capabilities to evaluate the performance of the agents in the crew based on the tasks they have performed",
             verbose=False,
-            llm=self.openai_model_name,
+            llm=self.llm,
         )
 
     def _evaluation_task(
diff --git a/tests/crew_test.py b/tests/crew_test.py
index 2003ddada..4e660542f 100644
--- a/tests/crew_test.py
+++ b/tests/crew_test.py
@@ -14,6 +14,7 @@ from crewai.agent import Agent
 from crewai.agents.cache import CacheHandler
 from crewai.crew import Crew
 from crewai.crews.crew_output import CrewOutput
+from crewai.llm import LLM
 from crewai.memory.contextual.contextual_memory import ContextualMemory
 from crewai.process import Process
 from crewai.task import Task
@@ -662,6 +663,33 @@ def test_task_tools_override_agent_tools_with_allow_delegation():
     assert isinstance(researcher_with_delegation.tools[0], TestTool)
 
 @pytest.mark.vcr(filter_headers=["authorization"])
+@pytest.mark.vcr(filter_headers=["authorization"])
+def test_crew_test_with_custom_llm():
+    tasks = [
+        Task(
+            description="Test task",
+            expected_output="Test output",
+            agent=researcher,
+        )
+    ]
+    crew = Crew(agents=[researcher], tasks=tasks)
+    
+    # Test with LLM instance
+    custom_llm = LLM(model="gpt-4o")
+    crew.test(n_iterations=1, llm=custom_llm)
+    
+    # Test with model name string
+    crew.test(n_iterations=1, llm="gpt-4o")
+    
+    # Test backward compatibility
+    crew.test(n_iterations=1, openai_model_name="gpt-4o")
+    
+    # Test error when no LLM provided
+    with pytest.raises(ValueError):
+        crew.test(n_iterations=1)
+
+
+
 def test_crew_verbose_output(capsys):
     tasks = [
         Task(
@@ -1123,7 +1151,7 @@ def test_kickoff_for_each_empty_input():
     assert results == []
 
 
-@pytest.mark.vcr(filter_headers=["authorization"])
+@pytest.mark.vcr(filter_headeruvs=["authorization"])
 def test_kickoff_for_each_invalid_input():
     """Tests if kickoff_for_each raises TypeError for invalid input types."""
 
@@ -3125,4 +3153,4 @@ def test_multimodal_agent_live_image_analysis():
     # Verify we got a meaningful response
     assert isinstance(result.raw, str)
     assert len(result.raw) > 100  # Expecting a detailed analysis
-    assert "error" not in result.raw.lower()  # No error messages in response
\ No newline at end of file
+    assert "error" not in result.raw.lower()  # No error messages in response