Action to Delegate : new Action or casting Action?

I found two different ways to initialize a Delegate with an Action :

Create a new action or casting to Action.

Delegate foo = new Action(() => DoNothing(param));
Delegate bar = (Action)(() => DoNothing(param));

Is there a difference between this 2 syntaxes?

Which one is better and why?

Delegate is use in this example because the syntaxes is useful to call methods like BeginInvoke or Invoke with a lambda expression, and it's important to cast the lambda expression into an action

static main 
{
    Invoke((Action)(() => DoNothing())); // OK
    Invoke(new Action(() => DoNothing())); // OK
    Invoke(() => DoNothing()); // Doesn't compil
}

private static void Invoke(Delegate del) { }

But it's interesting to see that the compiler authorized this :

Action action = () => DoNothing();
Invoke(action);