diff --git a/modules/images.py b/modules/images.py
index 87a7bf22..b6f2358c 100644
--- a/modules/images.py
+++ b/modules/images.py
@@ -321,7 +321,7 @@ def resize_image(resize_mode, im, width, height, upscaler_name=None):
     return res
 
 
-invalid_filename_chars = '<>:"/\\|?*\n\r\t'
+invalid_filename_chars = '#<>:"/\\|?*\n\r\t'
 invalid_filename_prefix = ' '
 invalid_filename_postfix = ' .'
 re_nonletters = re.compile(r'[\s' + string.punctuation + ']+')