diff --git a/keras/ops/numpy.py b/keras/ops/numpy.py
index c25f1c7489fa..2a8b74aadde6 100644
--- a/keras/ops/numpy.py
+++ b/keras/ops/numpy.py
@@ -2695,6 +2695,8 @@ def compute_output_spec(self, x, key):
             remaining_key = [key]
         elif isinstance(key, tuple):
             remaining_key = list(key)
+        elif isinstance(key, list):
+            remaining_key = key.copy()
         else:
             raise ValueError(
                 f"Unsupported key type for array slice. Recieved: `{key}`"