Poppy Montgomery as Marilyn Monroe in 'Blonde'

When I told my mother I got the part of Marilyn Monroe, she didn’t even bat an eyelash,” recalls Poppy Montgomery. ”She said, ‘Well, you’ve been rehearsing for it your whole life.’ ”

While the Australian-born ingenue might seem an odd choice to embody America’s classic sex symbol, the 25-year-old actress actually had no need of a Marilyn 101 crash course to star in CBS’ Blonde. She grew up with posters of the powder-skinned goddess plastered to her bedroom walls, has seen all of Monroe’s movies, and read her biography at the age of 12.

But what most impressed Blonde director Joyce Chopra about Montgomery was her interpretive approach to the role. ”Poppy in no way set out to imitate Marilyn,” says Chopra. ”And by not imitating, I think she achieved a resemblance and was able to create a living, breathing character.”

The only aspect of Monroe that Montgomery did try to copy was her Rubenesque figure. ”I was probably 12 pounds heavier when we shot Blonde,” says the wiry, self-described junk-food addict, who quit working out to gain weight for the part. Today, dressed for yoga, Montgomery screeches at the mention of a scene that features her round derriere in a snug white skirt. ”Who wants a close-up of their butt on camera? It was just so there, and it was mine,” she says. ”I should have gotten a body double!”

Like Monroe, Montgomery grew up at warp speed. The daughter of Nicola, a market researcher, and Phil, a restaurateur, Poppy Petal was raised in Sydney with sisters Rosie Thorn, Daisy Yellow, Lily Belle, Marigold Sun, and brother Jethro Tull. Montgomery dropped out of school at 14 and left home at 16 to travel around Bali with her boyfriend. Two years later, she headed to Florida on another romantic whim. Nearly out of cash in Sarasota, she hopped a Greyhound bound for Los Angeles.

”The bus driver bought me McDonald’s because I was so broke,” she says, sipping cappuccino just yards away from her silver Porsche. Camping out on an acquaintance’s couch, Montgomery sent a head shot every day to Julia Roberts’ former manager, Bob McGowan, until he signed her. ”I know it sounds like a made-up story,” says Montgomery, ”but it’s not.”

Today the persistent actress has a much more welcome problem: Having already tackled her ”dream role,” it’s become nearly impossible to choose her next project. ”It’s been hard for me to like anything else.”