Danny Martindale/WireImage | Tim Graham/Getty Images

The entire world is abuzz with the news that Kate Middleton is expecting her first child.

The news has delighted royal watchers, who have been speculating feverishly about a royal pregnancy since Middleton married Britain's Prince William on April 29, 2011.

If the 30-year-old Middleton has any doubts about how to embrace motherhood in the coming months, she can follow the example set by Princess Diana, William's late mother.

Royal watchers say Diana set the gold standard for mothering a future monarch.

"Diana lavished her boys with affection and she was truly a loving parent, which in many ways broke the mold for traditional royal parenting," Kate Coyne of People magazine told " Good Morning America."

Diana was just 20 years old when she announced she was pregnant with William, her first child.

For Complete Coverage of the Royal Baby, Please Visit Our Special Section - Click Here

The announcement came in November 1981, just three months after Diana wed Prince Charles in a wedding watched by an estimated 750 million people around the world.

Their older son's wedding eclipsed that. It was seen by a worldwide television audience of about 2 billion people.

Even before there was an official announcement that Diana was pregnant, the press had begun to speculate, particularly when she fell asleep while sitting up at a formal function.

Diana had no style equal, but even while she was pregnant, she continued to set trends by wearing clothes that were fashion-forward.

Pregnancy didn't deter her, either. She was ready and willing to perform her royal duties while she carried William, even though she suffered from morning sickness, though likely not as severe as Kate's.

The duchess was admitted to King Edward VII Hospital in central London yesterday with hyperemesis gravidarum, an acute morning sickness which requires supplementary hydration and nutrients, the palace said.

"Diana, funny enough, paved the way for this morning sickness," Ingrid Seward, editor in chief of the UK's Majesty magazine said today on " Good Morning America." "She had terrible morning sickness and she said the Royal Family never heard it."

"She was doing her duty and feeling absolutely ghastly so once again Diana is there, paving the way for Kate," Seward said.

Mothering Her Sons Her Way

William was the first royal baby to be born in a hospital. Diana reportedly was in labor for 16 hours before she gave birth to him at St. Mary's Hospital. She followed a natural childbirth plan - which included sucking ice, and Charles was by her side during her delivery.

PHOTOS: Kate Middleton Mirrors Princess Diana's Style

Word of William's birth was spread through a paper announcement that was attached to the gate of Buckingham Palace.

From the very beginning, Diana insisted on keeping her infant son by her side.

"Prince William was the first royal baby brought along on a royal trip," Coyne said, adding that Diana "insisted that she bring him. She would not leave him behind and one of the reasons was that she was breastfeeding - also unheard of in the royal family up until that time."

Two years later, when she gave birth to Harry, Diana's hands-on mothering style didn't change. She regularly played educational games with her young sons in their nursery, and was actively involved in dropping them off and picking them up from school in London.

Diana also opposed the tradition of sending off her sons to boarding school.

"In the royal family, children as young as 6 and 7 were sent away to boarding school, but that was not OK with Diana," Coyne said

Diana would go on to take her sons to such kid-favorite haunts as McDonald's in later years, notably insisting that William wait his turn in line to order. She also took her boys to amusement parks, famously going on rides with them.

Her goal? To give her children as normal a childhood as possible.

Years later, the princes would call Diana the best mother in the world.

Kate has some big maternal shoes to fill, but royal watchers predict she is up to the job.

"I think William and Kate's parenting styles might be similar to what Diana did," royal watcher Victoria Arbiter said. "And I think William and Kate are really going to follow that model and do everything they can to ensure as normal a childhood as possible, while at the same time behind the scenes educating their child for their future role."