addChild help (newbie to AS3)

I am experienced with AS2, but am very new to AS3. My question should be very easy to understand, but I have no idea on how to get it to work. I am trying to add a MC within a MC… so how do I do this?

This is what I have:

[AS]

i_parent.clip = new MovieClip();
i_parent.clip.addChild( /* the MC I want to attach */);

[/AS]

but this isn’t working as expected, I just errors and complaints :frowning:

Any help would great, thanks