Just over eight months after The New York Post declared her “Kirsten Dunce,” the actress Kirsten Dunst showed up in a Manhattan courtroom on Tuesday with a complete personality makeover.

Testifying in the trial of a man accused of burglarizing her hotel room in SoHo three years ago, Ms. Dunst came across as stern, exasperated and somewhat angry in her responses.

It was a drastic change from her performance – er, testimony – at the first trial last September, when she giggled away while on the witness stand. From the moment.

Ms. Dunst entered the courtroom then, she was smiling, greeting the gallery with a peppy, “Hi.” An article in The Post called her the “ditzy Dunst” and said she was “apparently at sea when it comes to speaking in public without the help of a Hollywood script.”

But on Tuesday, Ms. Dunst, sporting a bleach-blond bob, barely betrayed a smile, except when expressing frustration or incredulity at a defense lawyer’s questions.

“You, of course, don’t smoke pot, do you?” the lawyer asked her.

“I don’t,” Ms. Dunst said, even though the judge told her she did not have to answer the question.

James Jimenez is on trial on charges of entering the penthouse of Ms. Dunst and other actors in the SoHo Grand Hotel in August 2007 while they were filming the move “How to Lose Friends and Alienate People.” Mr. Jimenez’s lawyer has argued that the man his client was with that night was delivering drugs to Ms. Dunst’s entourage. One of Ms. Dunst’s friends, who also had her belongings stolen, testified that she did have marijuana in her bag.

Mr. Jimenez’s first trial ended with a hung jury.

After prodding from the defense lawyer, Ms. Dunst insisted there was no celebration after the crew  finished shooting that night. At some point during the evening, they ordered sushi from Nobu, she said.

“That was a treat for us,” she said.

After discovering that her belongings – including a brown Balenciaga handbag – and those of others had been stolen, Ms. Dunst said they alerted hotel security and the police. The police showed them surveillance tapes in which she said she saw, “two men getting out of the service elevator, coming into our room and walking out with that same bag that the sushi came in – but probably filled with our stuff.”