Rashi on Genesis 45:1/רש"י על בראשית מ״ה:א׳

1ולא יכל יוסף להתאפק לכל הנצבים AND JOSEPH COULD NOT REFRAIN HIMSELF BEFORE ALL THEM THAT STOOD — He could not bear that the Egyptians should stand by him witnessing how his brothers would be put to shame when he made himself known to them.