Fred Astaire and Eleanor Powell - Broadway Melody of 1940, the second half of the "Begin the Beguine" number. The first half was a tango, formal jacket and long white dress, the kind of stuff Fred did with all his partners, except that he didn't have to cover for Eleanor Powell or maneuver fancy steps around her. She could dance as well as he did.
And the second half was this-no fancy dress, no fuss, the two of them dancing side by side, full-length shot and one long, unbroken take. He tapped a combination, she echoed it, snapping the steps out in precision time, he did another, she answered, neither of them looking at the other, each of them intent on the music.
Not intent. Wrong word. There was no concentration in them at all, no effort, they might have made up the whole routine just now as they stepped onto the polished floor, improvising as they went.
They tapped, turning, and Eleanor danced Fred back across the floor, facing him now but still not looking at him, her steps reflections of his, and then they were side by side again, swinging into a tap cadenza, their feet and the swirling skirt and the fake stars reflected in the polished floor, in the screens.
Eleanor swung into a turn, not looking at Fred, not having to, the turn perfectly matched to his, and they were side by side again, tapping in counterpoint, their hands almost touching. Fred tapped out a ripple, and Eleanor repeated it, and glanced sideways over her shoulder and smiled at him, a smile of awareness and complicity and utter joy.