diff --git a/litellm/cost_calculator.py b/litellm/cost_calculator.py
index 9fe192bc4d4..cbdf2c77542 100644
--- a/litellm/cost_calculator.py
+++ b/litellm/cost_calculator.py
@@ -18,6 +18,7 @@ from litellm.constants import (
     DEFAULT_MAX_LRU_CACHE_SIZE,
     DEFAULT_REPLICATE_GPU_PRICE_PER_SECOND,
 )
+from litellm.litellm_core_utils.hidden_params import HIDDEN_PARAMS_ATTR
 from litellm.litellm_core_utils.llm_cost_calc.tool_call_cost_tracking import (
     StandardBuiltInToolCostTracking,
 )
@@ -2023,8 +2024,12 @@ def response_cost_calculator(
             response_cost = 0.0
         else:
             if isinstance(response_object, BaseModel):
-                if hasattr(response_object, "_hidden_params"):
-                    provider_response_cost: Final = get_response_cost_from_hidden_params(response_object.hidden_params)
+                if hasattr(response_object, HIDDEN_PARAMS_ATTR):
+                    hidden_params: Final = cast(
+                        dict[str, object] | BaseModel,
+                        getattr(response_object, HIDDEN_PARAMS_ATTR),
+                    )
+                    provider_response_cost: Final = get_response_cost_from_hidden_params(hidden_params)
                     if provider_response_cost is not None:
                         return provider_response_cost