diff --git a/optimum/intel/openvino/modeling.py b/optimum/intel/openvino/modeling.py
index 4d859be5ea..9408483166 100644
--- a/optimum/intel/openvino/modeling.py
+++ b/optimum/intel/openvino/modeling.py
@@ -129,8 +129,12 @@ def to(self, device: str):
         Use the specified `device` for inference. For example: "cpu" or "gpu". `device` can
         be in upper or lower case. To speed up first inference, call `.compile()` after `.to()`.
         """
-        self._device = str(device).upper()
-        self.request = None
+        if isinstance(device, str):
+            self._device = device.upper()
+            self.request = None
+        else:
+            logger.warning(f"device must be of type {str} but got {type(device)} instead")
+
         return self
 
     def forward(self, *args, **kwargs):
diff --git a/optimum/intel/openvino/modeling_diffusion.py b/optimum/intel/openvino/modeling_diffusion.py
index 154580812b..41f06936f8 100644
--- a/optimum/intel/openvino/modeling_diffusion.py
+++ b/optimum/intel/openvino/modeling_diffusion.py
@@ -88,7 +88,7 @@ def __init__(
         **kwargs,
     ):
         self._internal_dict = config
-        self._device = str(device).upper()
+        self._device = device.upper()
         self.is_dynamic = dynamic_shapes
         self.ov_config = ov_config if ov_config is not None else {}
         self._model_save_dir = (
@@ -330,8 +330,12 @@ def _from_transformers(
         )
 
     def to(self, device: str):
-        self._device = device.upper()
-        self.clear_requests()
+        if isinstance(device, str):
+            self._device = device.upper()
+            self.clear_requests()
+        else:
+            logger.warning(f"device must be of type {str} but got {type(device)} instead")
+
         return self
 
     @property
diff --git a/optimum/intel/openvino/modeling_seq2seq.py b/optimum/intel/openvino/modeling_seq2seq.py
index 089399a252..7e9f582799 100644
--- a/optimum/intel/openvino/modeling_seq2seq.py
+++ b/optimum/intel/openvino/modeling_seq2seq.py
@@ -282,12 +282,16 @@ def __init__(
             pass
 
     def to(self, device: str):
-        self._device = str(device).upper()
-        self.encoder._device = self._device
-        self.decoder._device = self._device
-        if self.use_cache:
-            self.decoder_with_past._device = self._device
-        self.clear_requests()
+        if isinstance(device, str):
+            self._device = device.upper()
+            self.encoder._device = self._device
+            self.decoder._device = self._device
+            if self.use_cache:
+                self.decoder_with_past._device = self._device
+            self.clear_requests()
+        else:
+            logger.warning(f"device must be of type {str} but got {type(device)} instead")
+
         return self
 
     @add_start_docstrings_to_model_forward(