This week, the actress's wish came true with news that the couple are expecting a baby, their third together, after Ella (10) and Jett (16) who tragically died 16 months ago. Preston's due date has not been announced but it's expected to be this autumn, shortly after her birthday in October -- when she'll turn 48.
The star's later-life pregnancy might raise a few eyebrows, but it's a phenomenon becoming increasingly common in Hollywood and the real world.
The Piano actress Holly Hunter (52) gave birth to twin boys in 2006 aged 47 and Desperate Housewives star Marcia Crosswas 44 when she delivered twin girls Savannah and Eden. Halle Berry and Nicole Kidman were both 41 when they had their first child, as was Salma Hayek when her daughter Valentina was born in 2007.
The actress spoke for women everywhere when she told Marie Claire magazine: "Motherhood is not for everyone. It is for me, but there's no reason women should feel rushed to have a child."
It's a philosophy that the average woman on the street seems to have bought into. In Ireland the average age for women giving birth for the first time is steadily rising, as is the number of women giving birth over 35. A decade ago, women over 35 accounted for 9pc of all first births, while now that figure stands at 14pc.
Fertility expert Sharon Murphy thinks this rise can be largely attributed to the cultural changes in the status of women. "Life has changed," she says.
"Most of our grandmothers would probably have been married by 18 and had children young but now women are more likely to marry late and have high-powered careers and jobs."
Sharon, a member of the Natural Network for reproductive health, trained under holistic reproductive specialist Zita West, and uses acupuncture to aid fertility.
Her treatment works hand in hand with IVF and she's seen increasing numbers of older women coming to her for help.
She says: "I have quite a mixed group of women who come to me but the majority would be over 35. Quite often they are women who work long hours, fly a lot, are very stressed and haven't realised how their own fertility works."
This observation is shared by parenting mentor Sheila O'Malley, who runs workshops and parenting website practicalparenting.ie. "I've definitely been aware of an increase in older parents in recent years," she says.
"There are more women coming in at the upper end of their 40s having 'change of life' babies."
But she doesn't believe age needs to be a prime factor in what makes a good parent.
She explains: "I think the old adage 'happy parent, happy child' is what matters and if you have a mum who is fulfilled and calm, then that matters more than what age she is."
She adds: "Older mums have a lot to offer that younger mums might not.
"After 40, I think most women have dealt with their own issues and are a lot calmer. They can bring a lot of mature life experience and often are in a more financially and emotionally secure place."
But despite the advantages of becoming a mum later in life, it's important to realise that pregnancy can become more difficult with age.
Courteney Cox (45) had a well-documented battle with fertility, suffering miscarriages and enduring cycles of IVF before giving birth to daughter Coco in 2004.
Sarah Jessica Parker (45) turned to a surrogate after admitting she'd made the decision after facing 'disappointment' when trying to expand her brood conventionally.
"It would be odd to have made this choice if I could have successful pregnancies since my son's birth," Parker told the chat-show host Billy Bush.
Sharon says it's important not to be too swayed by the ease at which Hollywood's older mums appear to 'have it all'. She says: "Whether they announce it or not, most of those women are not getting pregnant unaided.
"A 40-year-old woman has 40-year-old eggs and age is a massive factor in fertility. The success rate of IVF can increase dramatically with acupuncture but it's by no means a sure bet and women might need to look into other options such as donor eggs, to have a child."
Sheila agrees: "Being a mum is tough and there's no doubt that dealing with night feeds and lack of sleep is easier when you're younger.
"I also find a lot of women might not have the same support if they're having their first child late in life, as their peer group will already have been through it. And many mums who have left a busy corporate lifestyle to sit at home with a baby can find it quite difficult to adjust.
"That said, there are always going to be trials and tribulations for mums at any age. The most important thing is to get support and look after yourself. Attitude matters more than age."
