diff --git a/src/main/java/picocli/CommandLine.java b/src/main/java/picocli/CommandLine.java
index 9d001f5c4..b8dbd7ddf 100644
--- a/src/main/java/picocli/CommandLine.java
+++ b/src/main/java/picocli/CommandLine.java
@@ -14751,9 +14751,9 @@ public static final class HelpCommand implements IHelpCommandInitializable, IHel
                 description = "Show usage help for the help command and exit.")
         private boolean helpRequested;
 
-        @Parameters(paramLabel = "COMMAND", descriptionKey = "helpCommand.command",
+        @Parameters(paramLabel = "COMMAND", arity="0..1", descriptionKey = "helpCommand.command",
                 description = "The COMMAND to display the usage help message for.")
-        private String[] commands = new String[0];
+        private String commands;
 
         private CommandLine self;
         private PrintStream out;
@@ -14768,9 +14768,9 @@ public void run() {
             CommandLine parent = self == null ? null : self.getParent();
             if (parent == null) { return; }
             Help.ColorScheme colors = colorScheme != null ? colorScheme : Help.defaultColorScheme(ansi);
-            if (commands.length > 0) {
+            if (commands != null) {
                 Map<String, CommandLine> parentSubcommands = parent.getCommandSpec().subcommands();
-                String fullName = commands[0];
+                String fullName = commands;
                 if (parent.isAbbreviatedSubcommandsAllowed()) {
                     fullName = AbbreviationMatcher.match(parentSubcommands.keySet(), fullName,
                             parent.isSubcommandsCaseInsensitive(), self);
@@ -14783,7 +14783,7 @@ public void run() {
                         subcommand.usage(out, colors); // for compatibility with pre-4.0 clients
                     }
                 } else {
-                    throw new ParameterException(parent, "Unknown subcommand '" + commands[0] + "'.", null, commands[0]);
+                    throw new ParameterException(parent, "Unknown subcommand '" + commands + "'.", null, commands);
                 }
             } else {
                 if (outWriter != null) {
diff --git a/src/test/java/picocli/HelpSubCommandTest.java b/src/test/java/picocli/HelpSubCommandTest.java
index 2468cee53..45e70fa45 100644
--- a/src/test/java/picocli/HelpSubCommandTest.java
+++ b/src/test/java/picocli/HelpSubCommandTest.java
@@ -346,13 +346,13 @@ class App implements Runnable{ public void run(){}}
         String expected = String.format("" +
                 "Displays help information about the specified command%n" +
                 "%n" +
-                "Usage: <main class> help [-h] [COMMAND...]%n" +
+                "Usage: <main class> help [-h] [COMMAND]%n" +
                 "%n" +
                 "When no COMMAND is given, the usage help for the main command is displayed.%n" +
                 "If a COMMAND is specified, the help for that command is shown.%n" +
                 "%n" +
-                "      [COMMAND...]   The COMMAND to display the usage help message for.%n" +
-                "  -h, --help         Show usage help for the help command and exit.%n");
+                "      [COMMAND]   The COMMAND to display the usage help message for.%n" +
+                "  -h, --help      Show usage help for the help command and exit.%n");
         assertEquals(expected, sw.toString());
 
         sw = new StringWriter();
diff --git a/src/test/java/picocli/I18nTest.java b/src/test/java/picocli/I18nTest.java
index bb9d8e27c..2b8cf5a81 100644
--- a/src/test/java/picocli/I18nTest.java
+++ b/src/test/java/picocli/I18nTest.java
@@ -590,14 +590,14 @@ public void testLocalizeBuiltInHelp_Shared() {
                 "Shared header heading%n" +
                 "i18n-sub HELP command header%n" +
                 "%n" +
-                "Usage: i18n-top i18n-sub help [-h] [COMMAND...]%n" +
+                "Usage: i18n-top i18n-sub help [-h] [COMMAND]%n" +
                 "Shared description 0%n" +
                 "Shared description 1%n" +
                 "Shared description 2%n" +
-                "      [COMMAND...]   Shared description of COMMAND parameter of built-in help%n" +
-                "                       subcommand%n" +
-                "  -h, --help         Shared description of --help option of built-in help%n" +
-                "                       subcommand%n" +
+                "      [COMMAND]   Shared description of COMMAND parameter of built-in help%n" +
+                "                    subcommand%n" +
+                "  -h, --help      Shared description of --help option of built-in help%n" +
+                "                    subcommand%n" +
                 "Shared Exit Codes Heading%n" +
                 "These exit codes are blah blah etc.%n" +
                 "  00   (From shared bundle) Normal termination%n" +
@@ -625,14 +625,14 @@ public void testLocalizeBuiltInHelp_Specialized() {
                 "Shared header heading%n" +
                 "i18n-top HELP command header%n" +
                 "%n" +
-                "Usage: i18n-top help [-h] [COMMAND...]%n" +
+                "Usage: i18n-top help [-h] [COMMAND]%n" +
                 "Shared description 0%n" +
                 "Shared description 1%n" +
                 "Shared description 2%n" +
-                "      [COMMAND...]   Specialized description of COMMAND parameter of i18-top%n" +
-                "                       help subcommand%n" +
-                "  -h, --help         Specialized description of --help option of i18-top help%n" +
-                "                       subcommand%n" +
+                "      [COMMAND]   Specialized description of COMMAND parameter of i18-top help%n" +
+                "                    subcommand%n" +
+                "  -h, --help      Specialized description of --help option of i18-top help%n" +
+                "                    subcommand%n" +
                 "Shared Exit Codes Heading%n" +
                 "These exit codes are blah blah etc.%n" +
                 "  00   (From shared bundle) Normal termination%n" +