diff --git a/src/diffusers/pipelines/kolors/pipeline_kolors.py b/src/diffusers/pipelines/kolors/pipeline_kolors.py
index 2214c9ea2c58..97831a837f3e 100644
--- a/src/diffusers/pipelines/kolors/pipeline_kolors.py
+++ b/src/diffusers/pipelines/kolors/pipeline_kolors.py
@@ -885,15 +885,16 @@ def __call__(
                         callback_kwargs[k] = locals()[k]
                     callback_outputs = callback_on_step_end(self, i, t, callback_kwargs)
 
-                    latents = callback_outputs.pop("latents", latents)
-                    prompt_embeds = callback_outputs.pop("prompt_embeds", prompt_embeds)
-                    negative_prompt_embeds = callback_outputs.pop("negative_prompt_embeds", negative_prompt_embeds)
-                    add_text_embeds = callback_outputs.pop("add_text_embeds", add_text_embeds)
-                    negative_pooled_prompt_embeds = callback_outputs.pop(
-                        "negative_pooled_prompt_embeds", negative_pooled_prompt_embeds
-                    )
-                    add_time_ids = callback_outputs.pop("add_time_ids", add_time_ids)
-                    negative_add_time_ids = callback_outputs.pop("negative_add_time_ids", negative_add_time_ids)
+                    if callback_outputs is not None:
+                        latents = callback_outputs.pop("latents", latents)
+                        prompt_embeds = callback_outputs.pop("prompt_embeds", prompt_embeds)
+                        negative_prompt_embeds = callback_outputs.pop("negative_prompt_embeds", negative_prompt_embeds)
+                        add_text_embeds = callback_outputs.pop("add_text_embeds", add_text_embeds)
+                        negative_pooled_prompt_embeds = callback_outputs.pop(
+                            "negative_pooled_prompt_embeds", negative_pooled_prompt_embeds
+                        )
+                        add_time_ids = callback_outputs.pop("add_time_ids", add_time_ids)
+                        negative_add_time_ids = callback_outputs.pop("negative_add_time_ids", negative_add_time_ids)
 
                 if i == len(timesteps) - 1 or ((i + 1) > num_warmup_steps and (i + 1) % self.scheduler.order == 0):
                     progress_bar.update()
diff --git a/src/diffusers/pipelines/kolors/pipeline_kolors_img2img.py b/src/diffusers/pipelines/kolors/pipeline_kolors_img2img.py
index 4a35da47a50d..7eb15a1e8eee 100644
--- a/src/diffusers/pipelines/kolors/pipeline_kolors_img2img.py
+++ b/src/diffusers/pipelines/kolors/pipeline_kolors_img2img.py
@@ -1059,15 +1059,16 @@ def denoising_value_valid(dnv):
                         callback_kwargs[k] = locals()[k]
                     callback_outputs = callback_on_step_end(self, i, t, callback_kwargs)
 
-                    latents = callback_outputs.pop("latents", latents)
-                    prompt_embeds = callback_outputs.pop("prompt_embeds", prompt_embeds)
-                    negative_prompt_embeds = callback_outputs.pop("negative_prompt_embeds", negative_prompt_embeds)
-                    add_text_embeds = callback_outputs.pop("add_text_embeds", add_text_embeds)
-                    negative_pooled_prompt_embeds = callback_outputs.pop(
-                        "negative_pooled_prompt_embeds", negative_pooled_prompt_embeds
-                    )
-                    add_time_ids = callback_outputs.pop("add_time_ids", add_time_ids)
-                    negative_add_time_ids = callback_outputs.pop("negative_add_time_ids", negative_add_time_ids)
+                    if callback_outputs is not None:
+                        latents = callback_outputs.pop("latents", latents)
+                        prompt_embeds = callback_outputs.pop("prompt_embeds", prompt_embeds)
+                        negative_prompt_embeds = callback_outputs.pop("negative_prompt_embeds", negative_prompt_embeds)
+                        add_text_embeds = callback_outputs.pop("add_text_embeds", add_text_embeds)
+                        negative_pooled_prompt_embeds = callback_outputs.pop(
+                            "negative_pooled_prompt_embeds", negative_pooled_prompt_embeds
+                        )
+                        add_time_ids = callback_outputs.pop("add_time_ids", add_time_ids)
+                        negative_add_time_ids = callback_outputs.pop("negative_add_time_ids", negative_add_time_ids)
 
                 if i == len(timesteps) - 1 or ((i + 1) > num_warmup_steps and (i + 1) % self.scheduler.order == 0):
                     progress_bar.update()