diff --git a/fmpose3d/inference_api/README.md b/fmpose3d/inference_api/README.md
index 71a77b1..89d3761 100644
--- a/fmpose3d/inference_api/README.md
+++ b/fmpose3d/inference_api/README.md
@@ -97,7 +97,7 @@ Convenience constructor for the **animal** pipeline. Sets `model_type="fmpose3d_
 
 ### Public Methods
 
-#### `predict(source, *, camera_rotation, seed, progress)` → `Pose3DResult`
+#### `predict(source, *, camera_rotation, seed, progress, return_2d)` → `Pose3DResult`
 
 End-to-end prediction: 2D estimation followed by 3D lifting in a single call.
 
@@ -107,6 +107,7 @@ End-to-end prediction: 2D estimation followed by 3D lifting in a single call.
 | `camera_rotation` | `ndarray \| None` | Length-4 quaternion for camera-to-world rotation. Defaults to the official demo rotation. `None` skips the transform. Ignored for animals. |
 | `seed` | `int \| None` | Seed for reproducible sampling. |
 | `progress` | `ProgressCallback \| None` | Callback `(current_step, total_steps) -> None`. |
+| `return_2d` | `bool` | When `True`, include the intermediate 2D result under `Pose3DResult.pose_2d`. Default: `False`. |
 
 **Returns:** `Pose3DResult`
 
@@ -175,6 +176,7 @@ Source = Union[str, Path, np.ndarray, Sequence[Union[str, Path, np.ndarray]]]
 |---|---|---|
 | `poses_3d` | `ndarray` | Root-relative 3D poses, shape `(num_frames, J, 3)`. |
 | `poses_3d_world` | `ndarray` | Post-processed 3D poses, shape `(num_frames, J, 3)`. For humans: world-coordinate poses. For animals: limb-regularized poses. |
+| `pose_2d` | `Pose2DResult \| None` | Optional 2D prediction payload, present when `predict(..., return_2d=True)` is used. |
 
 
 
diff --git a/fmpose3d/inference_api/fmpose3d.py b/fmpose3d/inference_api/fmpose3d.py
index 603277d..003693c 100644
--- a/fmpose3d/inference_api/fmpose3d.py
+++ b/fmpose3d/inference_api/fmpose3d.py
@@ -477,6 +477,8 @@ class Pose3DResult:
     ``camera_to_world``).  For animal poses this contains the
     limb-regularised output.
     """
+    pose_2d: Pose2DResult | None = None
+    """Optional 2D prediction payload from :meth:`FMPose3DInference.predict`."""
 
 
 #: Accepted source types for :meth:`FMPose3DInference.predict`.
@@ -659,6 +661,7 @@ def predict(
         camera_rotation: np.ndarray | None = _DEFAULT_CAM_ROTATION,
         seed: int | None = None,
         progress: ProgressCallback | None = None,
+        return_2d: bool = False,
     ) -> Pose3DResult:
         """End-to-end prediction: 2D pose estimation → 3D lifting.
 
@@ -683,6 +686,9 @@ def predict(
         progress : ProgressCallback or None
             Optional ``(current_step, total_steps)`` callback.  Forwarded
             to the :meth:`pose_3d` step (per-frame reporting).
+        return_2d : bool
+            When ``True``, include the intermediate :class:`Pose2DResult`
+            in the returned :class:`Pose3DResult` as ``pose_2d``.
 
         Returns
         -------
@@ -690,13 +696,16 @@ def predict(
             Root-relative and world-coordinate 3D poses.
         """
         result_2d = self.prepare_2d(source)
-        return self.pose_3d(
+        result_3d = self.pose_3d(
             result_2d.keypoints,
             result_2d.image_size,
             camera_rotation=camera_rotation,
             seed=seed,
             progress=progress,
         )
+        if return_2d:
+            result_3d.pose_2d = result_2d
+        return result_3d
 
     @torch.no_grad()
     def prepare_2d(