For millions of movie lovers, Diane Keaton is and always will be the queen of quirky Hollywood heroines.

From her Oscar-winning portrayal of the vest-clad Annie Hall to "Something's Gotta Give's" frazzled Erica Barry, Keaton carved out a career that most actresses dream of but never achieve.

Yet after four decades of unimaginable success, Keaton is humble about her fame, her fashion icon status, and her romances with Woody Allen, Warren Beatty and Al Pacino.

"I was lucky," Keaton said on Friday in a taped interview aired on CTV's Canada AM.

"I work hard. I really do. But I wouldn't be here if it weren't for Woody Allen," Keaton told Canada AM co-host Marci Ien, who chatted with the star during a recent visit to Toronto.

The 66-year-old actress and L'Oréal spokesperson was in town to promote Age Perfect, the company's skincare line for mature women.

"I wasn't chosen because I'm a great beauty," said Keaton.

"I got the job because I was in ‘Something's Gotta Give,'" she said.

In the 2003 romcom, Keaton charmed audiences with her endearing portrayal of a 50-something woman who finds love for the first time with a carousing, self-satisfied playboy (Jack Nicholson).

"There's still romance after you're 50. There's still a life. There's still exciting adventures and there's still a newness to everything," said Keaton.

"There's a whole market for women out there who want to be attractive and who are over 50. Now we're getting some attention," she said.

Keaton's career, of course, continues to attract interest from studio execs and critics.

In her latest role, Keaton plays a dissatisfied wife opposite Kevin Klein in the 2012 ensemble comedy, "Darling Companion."

In 2011, Keaton also penned the bestselling memoir "Then Again," In it, Keaton took an unguarded look at her early life and her mother's 15-year struggle with Alzheimer's disease.

Her mother's influence on her life, by Keaton's own admission, was inestimable.

"My mother listened to me. She never told me what to think. She just let me talk. That's an extraordinary gift for a mother to give you," said Keaton.

Even so, Keaton's youth was riddled with insecurities.

"When I was a girl I was very insecure, very shy. But then I had that other side, the exhibitionist side that my mother encouraged," said Keaton.

The insecure Keaton also experienced health problems in her 20s, when she became bulimic during her affair with "Annie Hall" director, Woody Allen.

"My 20s were hard," said Keaton.

"When you leave home it's not so easy because who are you? How do you take on this new role of life? What do you do with it?" she said.

As she matured, Keaton learned to take care of herself. But even with her mother's encouragement, the lessons were difficult.

Today, Keaton takes great joy in helping her own children learn about life.

Keaton adopted her daughter, Dexter, in 1996, when she was 50.

She later adopted her son, Duke, in 2001.

"I really did it very late. I was very self-consumed with myself," said Keaton.

Looking back, the decision to tackle motherhood gave Keaton a new sense of who she was as person.

"The one clear, pure, true definition of who I am is: I'm a mother," said Keaton.

In fact, the actress could not hide her tears upon hearing a passage from "Then Again" read aloud by Ien. In it, Keaton shared her true feelings about the day she took her daughter home in a little basket.

"Dexter was my in sickness and health, 'till death to do us part -- unconditional love. She was my new family, this sturdy, resilient, alert girl from North Carolina," Keaton wrote.

"I'm such a jerk," Keaton said, as she wiped away her tears.

"That just moves me because I love them," she said.