The new prince may only be three days old, but he "behaves himself" and sleeps "well". On Wednesday, the new father of three Prince William joined an Anzac Day Service of Memoration and Thanksgiving in Westminster Abbey alongside brother Prince Harry and sister-in-law Meghan Markle. And when he arrived, he could not help but rave about the latest addition to his family, Kate Middleton.
When asked how the boy is doing, William, 35, said, "Very good, thanks."
He added that all are "in good shape, fortunately" and said his new son ̵
"Sleeping is going pretty well so far so he's behaving well," William said.
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William and Princess Kate's Baby Boy was born on Monday at 11:01 am local time in London. He weighed 8 lbs, 7 oz.
Mom and dad – who introduced their son to the world only seven hours after their birth – have already returned home to Kensington Palace, where they start life as a family of five
"It completes them," she said Royal biographer Ingrid Seward PEOPLE in the cover story of this week. A friend of the couple noted that Kate, 36, "is one of three siblings, and it's a good family size. Boy-Girl-Boy is also pretty cool."
RELATED: Watch The New Royal Baby Prince from every angle!
For much more about the new royal family of five, read this week's edition of PEOPLE, at kiosks Friday
Parenting, the friend added, "suits them very well. They enjoy it and are very happy. "
Big brother Prince George, 4, and big sister Princess Charlotte, who turns 3 on May 2," are so excited, "another friend said. "Kate is worried that Charlotte will be the youngest, but she's such a self-confident little girl and growing up so fast, Kate hopes she'll adapt."
RELATED VIDEO: Visit of Prince George and Princess Charlotte Royal Baby in the Hospital
Meanwhile, Anzac Day falls every year on April 25 – the anniversary of landings in the Dardanelles of 1915.
Although originally designed In honor of members of the Australian and New Zealand Army Corps who fought the Ottoman Empire in Gallipoli during the First World War, the day has now become a national day of remembrance for all dead soldiers and veterans in Australia and New Zealand.