Lambda expressions and the Action<Object> delegate

The Action<Object> delegate is used in RelayCommands, DelegateCommands.

Code snippets below:
  public class SimpleDelegateCommand : ICommand
    {
        Action<object> _executeDelegate;

          public SimpleDelegateCommand(Action<object> actionDelegate)
        {
            _executeDelegate = actionDelegate;
        }

etc.

 public class Methods
    {
       // A method that doesn't had any parameters
        public static void NoParameterMethod()
        {
            MessageBox.Show("The Method that doesn't take a parameter was Called");
        }

The question I have is: Why is the following acceptable?

       private ICommand _test2Command = new SimpleDelegateCommand(y => Methods.NoParameterMethod());

That is:
given that the SimpleDelegateCommand needs and Action<object> delegate to be passed as an argument, how can a method that doesn't take any parameters be allowed by the delegate?