The 70-year-old Trumbo actress has been married to director Taylor Hackford since 1997, and while she has two stepsons from her spouse's former marriage, she has never had children of her own. In a new interview, Helen reveals she thought she was secure in her choice not to become a mother - until she watched 1989 comedy movie Parenthood.

"I love children, they are so funny and so sweet, but I never wanted my own," she told Britain's Sunday Times' Culture magazine. "I have never had a moment of regret about not having children. Well, I lie. When I watched the movie, Parenthood, I sobbed for about 20 minutes."

The film stars Steve Martin and Rick Moranis, and tells the story of the Buckman family, who struggle with various aspects of their lives as parents, siblings and partners.

While it was marketed as a comedy, it had something of a different effect on Helen when she first watched it.

"It was about the whole story of being a parent and how it never stops, even when you’re a grandparent," she added. "I realised I would never experience that, and for about 20 minutes, I sobbed for the loss of that and the fact that I never experienced it.

"Then I got over it and I was happy again."

Helen is stepmother to Taylor's sons Rio and Alex. She is also an aunt and relishes the role, although she acknowledges it's still a far cry from the feelings she may have had as a mother.

"I’m quite relieved, actually," Helen added of not having her own children. "I can feel that kind of love for my extended family and of course it isn’t the same as 'that lioness love' – and I’m certainly not dissing it. But I feel I can be less judgmental as an aunt. You’re not so invested."