Tween function

Hello,

I wrote the code for a tween function called fadeOut. As you can understand, its end is to fade out the alpha property of an instance.

the code uses an addEventListener:

chooseBlue_btn.addEventListener(MouseEvent.CLICK, fadeOut);

so when the button named chooseBlue_btn is clicked the fadeOut is called:

function fadeOut(e:Event):void
{
chooseRed.x +=1 ;
var tweenfadeOut:Tween = new Tween(buttonV, “alpha”, None.easeOut, 1, 0, 3, true);
}

But I would like to call fadeOut when the clip starts without using a button.
In which way?

Thank you.