While the Renée Zellweger-Ewan McGregor '60s romantic comedy spoof "Down with Love" may have quickly gone down the tubes in America last summer, the British premiere Thursday night kicked off in true London fashion, reports PEOPLE.

That is, it rained. But Zellweger wasn't about to let a little moisture, or even her new poundage for her next "Bridget Jones" movie, dampen her spirits. (Costar McGregor, 32, however, did not attend the event, due to filming duties for the upcoming "Star Wars III.")

Looking radiant in a mod, off-the-shoulder and unrevealing black woolen Prada dress and snakeskin stiletto boots, Zellweger, 34, obligingly fielded questions about the movie ("It was so much fun," she drawled) and her weight gain for "Bridget Jones: The Edge of Reason."

Regarding "Bridget," who is notoriously plumper than the slim and trim Roxie Hart of "Chicago," Zellweger, when asked how she was hiding her heft at the "Love" premiere, said between peals of laughter: "I'm hiding it behind my coat!"

She then went on to explain, "It's really just math. I've been eating lots of really fattening food. I read that I'd been eating doughnuts, but they're not really my thing."

According to Zellweger, whose work with a nutritionist includes being fed healthy food with hidden fat, her weight gain plan is "all in the mouth. I'll just be doing something else on the side, reading scripts, in rehearsal, and people put food in front of me - I don't even notice it. It's a job, that's all. Just a job."

That job, according to British tabloid the Mirror, includes the consumption of pizza and Guinness. It's a dirty job, Renee, but someone's got to do it.