The stars, in the middle of the press junket for their upcoming film, "The Ugly Truth," exited to restaurant Il Cielo with the press corps, where the junket continued. Access Hollywood's Shaun Robinson was among the journalists attending the junket.
The upscale hotel's 400 guests were also forced to leave the building while police investigated. The bomb threat was phoned in – ultimately, no suspicious materials were discovered and guests were allowed to return after two hours.
But on a lighter note, Katherine told Shaun that it wasn't the only scary thing involving the film.
"I did hear this a lot as I was walking out of the theater [at the premiere], women going, 'Oh yeah, now I get it,'" she told Shaun on Saturday of Gerard's character's feminine advice. "Are you really taking away from this any sort of insight? That's terrifying!"
Instead, she hopes the romantic comedy helps give people a "middle ground" in approaching relationships.
"The point was to find that middle ground," she said. "The two extremes find a middle ground."
And less "terrifying" is her new redheaded 'do, which she was able to get thanks to her "Grey's Anatomy" character, Izzy Stevens, going bald.
"It's gonna be fun," she laughed. "I'm usually not able to do that because Izzie's blonde, but Izzie's bald now so I could do whatever I want."
Still, she said, her blonde locks will be back soon enough, if husband Josh Kelley has anything to say about it.
"I'd give it three months and he's gonna want the long blonde hair because men are very predictable," she said. "Which this movie makes clear."
Related Content from AccessHollywood.com:
PLAY IT NOW: Katherine Heigl's 'Ugly Truth' Premiere (July 16, 2009)
PLAY IT NOW: Behind The Scenes: 'The Ugly Truth'