Live-action film shot, one continuous shot, no cuts, no scene change, the camera

Live-action film shot, one continuous shot, no cuts, no scene change, the camera stays in the same place for the whole clip. A grand golden ballroom with mirrors and chandeliers. A man in a black overcoat is in a deep elegant bow on the right, one hand held out to a woman in a red gown on the left. A tiny old janitor with a mop stands between them. She raises one eyebrow, takes the mop from the...