Traffic on West 45th has come to a halt. Hundreds of people have spilled from the sidewalk onto the street. Screams can be heard halfway down the block through a closed, double-pane sixth-floor window. This is no ordinary Broadway show; this is Pretty Woman-induced pandemonium.

Julia Roberts (pictured) has now completed two days (and three shows) in Three Days of Rain, and by all accounts she’s received a warm welcome from 3,000 or so theatergoers. We hear that after her first line — ”Yes” — she gets a thunderous (and distracting) burst of applause and then turns in a polished, professional performance as the buttoned-up daughter of a famous architect and (in Act 2) as her eccentric Southern mother. In fact, she looks far more comfortable on stage, commented one viewer, than fellow Oscar winner Denzel Washington did in last season’s Julius Caesar.

One quibble from a serious theatergoer: Audiences seem to be extremely distracted by the star’s presence; they crane their necks, they fidget, they wonder (often aloud) ”What’s Julia doing now?” — rather than focusing on the show as a whole. (Shame, since it’s a gorgeous piece of playwriting.) ”It’s a little like she’s on display,” said one lucky ticketholder. Still, lots of folks were on their feet at the curtain call — which Roberts shares with costars Paul Rudd and Bradley Cooper (who’s getting major buzz for his appealing turn as a self-involved actor and, later, as the aforementioned architect’s self-involved partner).

And here’s a little warning for anyone seated in the first couple rows: Wear something waterproof. It’s not called Three Days of Rain for nothing.