[How to create a TweenLite but not start it immediately]

I can create a TweenLite like this:

 

var tl = TweenLite.from( '.box', 1, {opacity:0} );

 

At this point it automatically plays.

 

How can I get it to not auto-play, but instead "manually" start it at a later time with:

 

tl.play();