"Penelope," which debuts in major U.S. cities on Friday, has been a pet project for the star who, along with producing partner Jennifer Simpson, worked four years to develop and make the quirky contemporary fable about a rich girl, played by Christina Ricci, who is cursed with a pig's nose.

"This was the first film that we found the script, found the director and did all the heavy lifting," said Witherspoon.

Her company, Type A Films, also produced "Legally Blonde 2: Red, White & Blonde." But on that movie, Witherspoon took the starring role and was credited as executive producer, which is often more of an advisory role. As producer on "Penelope," Witherspoon was involved in various ways including script development, casting, production, editing and distribution.

The 31-year-old producer said the story of "Penelope" was perfect for a Type A personality because, among other reasons, it spoke to some big issues yet centered on a young woman.

"It had a really great female character who was strong, ambitious, but definitely had a journey to go through to get to the place where she would find herself," Witherspoon said.

Penelope's wealthy socialite parents unsuccessfully try to break a family curse by marrying off their disfigured daughter to a rich suitor. But the lonely girl meets a handsome stranger (James McAvoy) and decides to flee her gilded cage.

Out in the real world for the first time, Penelope is befriended by free spirit Annie (Witherspoon) who whisks her new girlfriend around London on the back of a scooter, ultimately helping to restore Penelope's self-esteem.

If the role of Penelope sounds like it might have worked well for Witherspoon, a petite blonde who won her Oscar playing country singer June Carter in "Walk the Line," the star would not disagree. She said she thought about taking the lead role, but other commitments kept her from doing so.

"It's very freeing to play a supporting character," she said. "Those are the kind of parts I came up playing, so it was kind of nice to return to that."

Having decided against playing the lead, Witherspoon the producer began casting. She said Ricci was her first choice, and added that she had always admired the fellow actress' fierce intelligence and sharp wit.

"We grew up auditioning together so it was great to finally have that collaboration we had talked about for so many years," Witherspoon said.

As for "Atonement" star McAvoy, she admits to being lucky to enlist him before that Oscar-nominated romantic drama put the actor on the list of stars on the rise in Hollywood.

"We were just lucky to get James. He's become this big movie star now. I tease him and say, "'I got you when you were cheap.' I'll never get him again," she said.

Witherspoon sees producing as a natural progression after being on movie sets for 15 years.

"I got to learn a lot ... things I don't normally get to touch," she said.