diff --git a/lib/ai/providers/fal-image.ts b/lib/ai/providers/fal-image.ts
index 930815fe8..deb39fe3a 100644
--- a/lib/ai/providers/fal-image.ts
+++ b/lib/ai/providers/fal-image.ts
@@ -695,6 +695,7 @@ function buildFalRequestPayload(params: {
       normalizeOptionalHttpUrl(params.imageParams?.falMaskImageUrl) ||
       normalizeOptionalHttpUrl(params.imageParams?.maskImageUrl);
     if (maskImageUrl) {
+      input.mask_image_url = maskImageUrl;
       input.mask_url = maskImageUrl;
     }