diff --git a/src/diffusers/pipelines/stable_diffusion_3/pipeline_stable_diffusion_3.py b/src/diffusers/pipelines/stable_diffusion_3/pipeline_stable_diffusion_3.py
index 660d9801df56..921aa5417258 100644
--- a/src/diffusers/pipelines/stable_diffusion_3/pipeline_stable_diffusion_3.py
+++ b/src/diffusers/pipelines/stable_diffusion_3/pipeline_stable_diffusion_3.py
@@ -344,8 +344,8 @@ def _get_clip_prompt_embeds(
     def encode_prompt(
         self,
         prompt: Union[str, List[str]],
-        prompt_2: Union[str, List[str]],
-        prompt_3: Union[str, List[str]],
+        prompt_2: Union[str, List[str]] = None,
+        prompt_3: Union[str, List[str]] = None,
         device: Optional[torch.device] = None,
         num_images_per_prompt: int = 1,
         do_classifier_free_guidance: bool = True,