Johansson has won rave reviews for her role in the Arthur Miller play, in which she portrays a 17-year-old girl in 1950s New York opposite Liev Schreiber, who plays her uncle.
But less than a month after her Broadway debut (24Jan10), the Lost in Translation beauty admits she is a wreck when she comes home to husband Ryan Reynolds.
She says, "I lost all track of time. Eight shows a week, two shows Wednesday and two shows Saturday - it's a workout. It's a real mental workout. I really have lost all track of time. I'm really a shell of my former self. It is exhausting. I actually can't quite express how exhausting it is."
Johansson's limited run is scheduled to end on 4 April (10).