Charlize Theron is addicted – to Howie Mandel's game show Deal or No Deal, according to the actress's director, Paul Haggis.

While shooting their new film, In the Valley of Elah, on location in Albuquerque, N.M., "I went to Charlize's trailer to talk to her about a scene, and I heard these really strange sounds inside," Haggis told PEOPLE Wednesday at a screening of Elah in New York's Sag Harbor. "I heard Howie Mandel's voice. Inside the trailer, she was watching the video-[game] version of Deal or No Deal."

Haggis, who'd never seen the show before, said Theron, 32, told him: "'Shh ... shh ... shh. He's offering the guy $200,000.' I said, 'Charlize, the guy's offering you $200,000 – take the money," said Haggis. "And she said, 'No, no, no. I'll wait for more.'"

Continued Haggis, "Then it went to $300,000, and I was like, 'Charlize, take the money, it's $300,000.' It got to $600,000, $700,000. I was screaming at the top of my lungs, 'Take the money! Take the money! Take the money!' And she was saying, 'No, no.' She was addicted to the show."

On set, Haggis described Theron, who won an Oscar for 2003's Monster, as an utter professional, but said that on breaks from filming the drama – about an Iraq war veteran who disappears just days after returning home to the United States – "Charlize would say, 'Excuse me, Paul. I have to go prepare.' And she'd go back and they'd be playing Deal or No Deal."