diff --git a/types/tail/index.d.ts b/types/tail/index.d.ts
index c2135bc079..965f2a9deb 100644
--- a/types/tail/index.d.ts
+++ b/types/tail/index.d.ts
@@ -6,7 +6,7 @@
 
 declare namespace Tail {
     interface TailOptions {
-        separator?: string | RegExp;
+        separator?: string | RegExp | null;
         fromBeginning?: boolean;
         fsWatchOptions?: Record<string, any>;
         follow?: boolean;