1. Stand your talent on a turntable in front of a greenscreen. Turn them while they're kissing (or whatever you're having them do). You could shoot it 360 degrees, but that takes a lot more greenscreen, which will cost a lot more than a turntable. (A motorized turntable might be ideal, as it will allow a consistent spin.)
Since you don't see their feet, and they aren't in physical contact with anything in the room, matching the movement shouldn't be too difficult as long as you're close. Time how long it takes to do each quarter turn, and match the background plates:
2. Set up a tripod and do a slow pan around the first space. (Okay, this is a bit of a trick -- really you should set up a circular dolly track and move it in a circle, but unless you need the parallax of foreground elements you can probably get away with a tripod.
3. Same thing with the second space.
What's better is to rent a motion-control / motorized tripod head so you can pan the camera at the exact same speed in each place. With this approach, you could shoot each space multiple times, removing different parts of the scene, so your backgrounds could fade in piece by piece (first the empty room, then the chair, then the mirror, etc). Also, you could pan your camera at a much slower speed and then time remap it to approximate the movement of your spinning actors.
When you do the final composite, consider animating the levels / color of your talent as they change spaces. If you're feeling really creative, then fade up different lighting as you shoot the greenscreen footage (maybe add a fill light, or a really bright rim light). Any of these methods will help to sell the effect.