You guys are all too young.![]()
They're not cutouts. The fine hairs at the edges of her hairstyle cinch that.
Yes, it could be rear projection, but portrait photographers have used front projection techniques for decades, and it's just as likely, if not moreso, to be that.
In short, front projection has the subject (in this case, actor) pose in front of a screen of retroreflective material, like scotchlite. The camera points straight at the screen. Between the camera and the subject is a half-silvered mirror called a beam-splitter set at a 45 degree angle. A slide projector points into the same mirror from 90 degrees to the camera. The projected image (background) hits the mirror, is deflected to the screen, and the retroreflective material bounces it straight back and through the half-silvered mirror right into the camera lens. Since the subject/person is nowhere near as reflective as the screen, you don't see the projected image on them. It's old school optical trickery. The bulk of the opening Dawn of Man sequence in 2001: A Space Odyssey is shot using this trick, as all the backgrounds there are large photographic plates shot in Africa.
Thank you so much for the explanation. I had no idea how it might have been done in the film era