The piano in ensemble. The piano in real life.
I think it's Tasso Janopoulo (I may have the spelling wrong). He's also the pianist on old encore recordings with Jacques Thibaud (old as in the 1920s, that is).
Thanks, rjm. Janopoulo also plays on the Fontaine d'Aretheuse cinephonie film with Thibaud (see 1/30/07 posting with embedded video), although only his hands are shown in the film.