As Prince William counts down the days until his wife, the Duchess of Cambridge, gives birth to the couple's first child, the spotlight is again on his mother, Princess Diana, who would have turned 52 years old today.

Diana, who died in a car crash in 1997 at the age of 36, has left a legacy for the kind of mother Kate, 31, will be when she gives birth to the couple's first child this month.

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"Diana was a fabulous mother," Ingrid Seward, editor-in-chief of Majesty Magazine, told ABC News. "She [Kate] will want to bring their child up with some of the values William had."

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Diana, royal experts say, taught Prince William, 31, and his brother, Prince Harry, 28, their values by example through her charity work with landmine victims and people living with AIDS.

She also broke the years of traditions in the royal household by openly showering her boys with love and demanding they be included on royal trips taken by her and the boys' father, Prince Charles, including a trip to Australia when William was an infant.

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"They said, 'Well, no, royal babies don't go on these tours,'" Arthur Edwards, royal photographer for The Sun, recalled of the palace's response. "She said, 'William doesn't go, I don't go.'"

Likewise, it has been said that Kate and William plan to raise their child without the help of an entourage of nannies and staff, relying instead on the help of Kate's mom, Carole Middleton, and themselves.

"She will be a full-time mum and, I think, at that stage she will do it by herself, really," ABC News' royal contributor Victoria Murphy said last month, referring to Kate's planned maternity leave from royal duties. "When her timetable starts up again, I think they will, at that stage, look to get some help, absolutely. And it's an incredibly important job."

Around the time of his 2011 wedding to Kate, Prince William himself recalled his mother fondly as a hands-on mom and his own disappointment that she never got to meet Kate, whom he met while in college.

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"She played a huge part in my life and Harry's growing up in how we saw and experienced things," he said of Diana.

"It's the one time since she's died I've thought to myself how fantastic if she was here," William said of his wedding day. "I'm just very sad she's never going to get a chance to meet Kate."

In an interview at the same time, Prince Harry agreed with his older brother.

"She would have loved, loved Kate," he said of their mom.