The Oscar winner is an ageless beauty but that didn't stop her from getting anxious about her landmark birthday in January last year (15).

"I rehearsed 50," she told More magazine. "I kind of stared at it a long time. I wasn't going to let it terrify me."

A year on, the 51-year-old is a lot more comfortable with her age and how she approaches life, and she no longer makes apologies for herself.

"My relationship with ageing is cosy," she added. "I'm not trying to play 29 and holding on with white knuckles, you know? I'm done saying, 'I'm sorry I wasn't who you needed or wanted me to be' to everybody in my life.'"

While Diane has had major success as an actress, winning an Academy Award for her role in 2002 film Unfaithful, she didn't do quite so well as a model in her younger years, having been turned down by Ford models co-founder Eileen Ford.

"Imagine if somebody said your nose is too big or your ears stick out," she said. "For me, it was my neck was too short, it stuck with me all my life."

In fact, despite her slim physique and youthful looks, Diane insists she has insecurities about her body as much as anyone else.

"The largest room in the world is room for improvement," she said. "You know, some mornings my thighs are fat. Some days my hair looks great. That's the human condition. Things hurt me just as much as anyone else. My insecurities, failures. I'm vulnerable to comparisons."