diff --git a/lib/command.js b/lib/command.js
index 907962f56..8870d29de 100644
--- a/lib/command.js
+++ b/lib/command.js
@@ -1099,9 +1099,9 @@ Expecting one of '${allowedValues.join("', '")}'`);
     }
 
     // Fallback to parsing the help flag to invoke the help.
-    if (this._helpOption.long) {
-      return this._dispatchSubcommand(subcommandName, [], [this._helpOption.long]);
-    }
+    return this._dispatchSubcommand(subcommandName, [], [
+      this._helpOption.long || this._helpOption.short
+    ]);
   }
 
   /**
@@ -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 73c606a5d..695c3bd25 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.