diff --git a/TTS/utils/audio/numpy_transforms.py b/TTS/utils/audio/numpy_transforms.py
index b701e767..af88569f 100644
--- a/TTS/utils/audio/numpy_transforms.py
+++ b/TTS/utils/audio/numpy_transforms.py
@@ -201,7 +201,6 @@ def stft(
 def istft(
     *,
     y: np.ndarray = None,
-    fft_size: int = None,
     hop_length: int = None,
     win_length: int = None,
     window: str = "hann",