diff --git a/index.d.ts b/index.d.ts
new file mode 100644
index 0000000..f3203d2
--- /dev/null
+++ b/index.d.ts
@@ -0,0 +1,7 @@
+declare module 'gatsby-plugin-mailchimp' {
+  export default function addToMailchimp(
+    email: string,
+    fields?: object,
+    endpointOverride?: string
+  ): Promise<object>;
+}