diff --git a/types/office-js-preview/index.d.ts b/types/office-js-preview/index.d.ts
index 961582b49ce908..38a5fa92db1ed8 100644
--- a/types/office-js-preview/index.d.ts
+++ b/types/office-js-preview/index.d.ts
@@ -93579,6 +93579,17 @@ declare namespace Word {
          * @param documentCompareOptions Optional. The additional options that specifies the behavior of comparing document.
          */
         compare(filePath: string, documentCompareOptions?: Word.DocumentCompareOptions): void;
+        /**
+         * Displays revision marks that indicate where the specified document differs from another document.
+         *
+         * @remarks
+         * [Api set: WordApi BETA (PREVIEW ONLY)]
+         * @beta
+         *
+         * @param base64File Required. The Base64-encoded content of the document with which the specified document is compared.
+         * @param documentCompareOptions Optional. The additional options that specify the behavior for comparing the documents. Note that the `compareTarget` option isn't allowed to be `CompareTargetSelected` in this API.
+         */
+        compareFromBase64(base64File: string, documentCompareOptions?: Word.DocumentCompareOptions): void;
         /**
          * Deletes a bookmark, if it exists, from the document.
          *