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Kate Middleton, the newest addition to the British royal family, captivated her country and the rest of the world last April when she married Prince William in an opulent ceremony.

In her latest royal act, the princess delivered her first speech to rave reviews.

How did her performance compare with William's late mother, England's beloved Princess Diana? According to Dickie Arbiter, royal commentator and former press secretary to the queen, Middleton passed with flying colors in a high pressure situation.

"The eyes and ears of the world were on her," Arbiter told ABC News, saying watchers were "hanging on every word."

Kate's first public address took place at the opening of The Treehouse, a hospice run by East Anglia's Children's Hospices in Ipswich, England. It supports children with life threatening illnesses and their families.

She spoke to the children, families, and hospice workers, saying she was proud to be a patron of the charity.

"When I first visited the hospice in Milton, I had a pre-conceived idea as to what to expect," she said. "Far from being a clinical, depressing place for sick children, it was a home. Most importantly, it was a family home, a happy place of stability, support and care. It was a place of fun."

Not only was it Middleton's first public speech, it was her first public speech alone. Prince William is completing a six-week Royal Air Force deployment in the Falkand Islands.

In just about everything she does, from what she wears to how she speaks, Middleton has been compared to her late mother-in-law. According to Arbiter, Middleton may have had a head start on Lady Di.

"When you start to draw comparisons of Diana coming into the Royal Family in 1981, and Kate coming into the Royal Family in 2011, it is very different," Arbiter said.

"Diana was 20 when she came in. Kate was 30," he said. "Kate had a university education, Diana didn't. Kate had an 8-year relationship with William before she got married to him. Diana barely had an 8-month relationship with Charles … Kate's had 10 years of growing up. Diana didn't."

Arbiter also gives credit to Kate's teacher - her husband.

"Kate had eight years of learning through William," he said. "She had the best teacher in the world. And she learned from him so when she came onto the scene last year in April … she already knew what she had to do. She already knew how to behave."

But there was one major difference between the two speeches.

Diana, said Arbiter, "said very little in the town hall in Cardiff, [Wales] right at the end of the tour, but what she did say had everyone congratulating her because she spoke in Welsh, which is quite something for anybody."

"And that went down very well," he added. "We still have yet to see something like that from Kate. It's not going to happen for a long time, that sort of thing."

But overall, Arbiter said Middleton's first speech was a success.

"Ten of ten," he decreed. "Eleven out of ten. She did brilliantly."