Star quality is a mysterious thing. We can't produce it, can't really measure it, can't really define it either. Some of the most beautiful people can't exude a watt of star power, while a potato-faced troll may be a virtual nuclear reactor of the stuff.
Marlene Dietrich has so much of it that she threatens to burst out of the screen in this 1930 screen test cut by Josef von Sternberg for DER BLAUE ENGEL (THE BLUE ANGEL). She smokes a cigarette in the toughest/most seductive way imaginable, sings a bit, upbraids her pianist, sings some more, then climbs atop the piano to show off her legs. It's magnificent.
Can't embed it here, but you can click here and watch it.