Melanie Lynskey made Peter Jackson's ''Heavenly Creatures'' 18 years ago. But ''Hello I Must Be Going'' feels like a new beginning.

You’d think Hollywood would have learned from its own rom-coms, but apparently not, because its dream girl has been right there all along.

The shy, sweet, and hilarious Melanie Lynskey debuted alongside Kate Winslet in 1994, playing a scowling teenage murderess in Peter Jackson’s riveting Heavenly Creatures. Since then she’s slowly become familiar as a stepsister (Ever After), wacky neighbor (TV’s Two and a Half Men), teary bride-to-be (Up in the Air), doe-eyed housewife (The Informant!), and messed-up mom (Win Win). Now, with the new romantic dramedy Hello I Must Be Going, her name is no longer on the tip of your tongue — it’s above the title.

The New Zealand-born actress, 35, stars as Amy, an out-of-work divorcée who moves back in with her parents and unwittingly regresses into a sullen teenager until she meets an actual teenager (Christopher Abbott, of HBO’s Girls) looking for someone more mature. A sexy romance blossoms. So does Lynskey.

”It is an amazing thing to be able to carry a character through an entire story line,” she says over coffee near her home in Los Angeles. ”Amy starts out the movie and she’s nothing — she’s just a shell of a person. She doesn’t even have a hobby. She doesn’t have belongings. She has a T-shirt! And a pair of denim cutoffs.”

Midway through the movie she ends up casting off both for a steamy (and funny) skinny-dipping sequence with Abbott. It was a welcome change for the actress, who recalls being described in reviews for Heavenly Creatures as ”dumpy and overweight” — and who found the audition process just as withering when she came to Hollywood at 18. ”My first-ever meeting with a casting director was like, ‘I don’t know why you’re here. You’re not going to work in America. You don’t have the right look. You’re not pretty enough…”’ Lynskey sighs. ”It was a horrible feeling of just trying to not cry.”

With Hello I Must Be Going, director Todd Louiso — a character actor himself — has finally given her a movie that allows her to be gorgeous.