diff --git a/lib/command.js b/lib/command.js
index 590a271dd..e014d957f 100644
--- a/lib/command.js
+++ b/lib/command.js
@@ -1807,7 +1807,7 @@ Expecting one of '${allowedValues.join("', '")}'`);
    *
    * You can optionally supply the  flags and description to override the defaults.
    *
-   * @param {string} str
+   * @param {string} [str]
    * @param {string} [flags]
    * @param {string} [description]
    * @return {this | string} `this` command for chaining, or version string if no arguments
diff --git a/typings/index.d.ts b/typings/index.d.ts
index 695c3bd25..73c606a5d 100644
--- a/typings/index.d.ts
+++ b/typings/index.d.ts
@@ -293,7 +293,7 @@ export class Command {
    *
    * You can optionally supply the  flags and description to override the defaults.
    */
-  version(str: string, flags?: string, description?: string): this;
+  version(str?: string, flags?: string, description?: string): this;
 
   /**
    * Define a command, implemented using an action handler.