Not for all of them. You have to put a little bit on each star, right in the middle. Like this...

[He flips the star in his plastered hand over, but it falls on the floor. Looking irritated, he ignores it and flicks one of the stars in the bucket onto it's back with a single finger, holding the putty in between two others.

When the star rolls over, he sticks the tack to it's back firmly, and then picks the whole thing up triumphantly to show Nill.]

See? Now it'll stick.