Princess Kate, Prince William debut newborn son as they leave hospital for Kensington Palace

PHOTO: Prince William and Catherine Duchess of Cambridge leave the hospital with their newborn baby boy at the Lindo Wing, St Marys Hospital, London, April 23, 2018.PlayTim Rooke/REX via Shutterstock
WATCH It's a boy: Kate gives birth to a new prince

The world got its first look at the newest member of Britain's royal family today as Prince William and Princess Kate debuted him outside the London hospital where Kate gave birth.

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Kate's red dress by designer Jenny Packham drew immediate comparisons to the red dress the late Princess Diana wore when she left St. Mary's Hospital in 1982 with William's younger brother, Prince Harry.

PHOTO: Prince Charles and Princess Diana, leave St. Marys Hospital with their new baby son, Prince Harry, Sept. 16, 1984, in London | Duke and Duchess of Cambridge leave St Marys Hospital after the birth of their 3rd child, April 23, 2018, in London. AP | Splash News
Prince Charles and Princess Diana, leave St. Mary's Hospital with their new baby son, Prince Harry, Sept. 16, 1984, in London | Duke and Duchess of Cambridge leave St Mary's Hospital after the birth of their 3rd child, April 23, 2018, in London.

Kate, 36, held her third child -- who weighed 8 pounds, 7 ounces at birth -- as she exited St. Mary's Hospital alongside William. Kate delivered the baby at 11:01 a.m., local time today, according to Kensington Palace.

PHOTO: Prince William and Catherine Duchess of Cambridge leave the hospital with their newborn baby boy at the Lindo Wing, St Marys Hospital, London, April 23, 2018. Tim Rooke/REX via Shutterstock
Prince William and Catherine Duchess of Cambridge leave the hospital with their newborn baby boy at the Lindo Wing, St Mary's Hospital, London, April 23, 2018.
PHOTO: Prince William and Catherine Duchess of Cambridge leave the hospital with their newborn baby boy at the Lindo Wing, St Marys Hospital, London, April 23, 2018. Tim Rooke/REX via Shutterstock
Prince William and Catherine Duchess of Cambridge leave the hospital with their newborn baby boy at the Lindo Wing, St Mary's Hospital, London, April 23, 2018.

William, 35, was present for the baby's birth in the Lindo Wing of St. Mary’s Hospital.

He departed the hospital a few hours after the baby's birth was announced, and later returned with the baby's older siblings, Prince George, 4, and Princess Charlotte, who turns 3 on May 2.

Princess Charlotte of Cambridge, Prince George of Cambridge by their father Britains Prince William, Duke of Cambridge, at the Lindo Wing of St Marys Hospital in London, April 23, 2018, to visit Catherine, Duchess of Cambridge, and their new-born son. Ben Stansll/AFP/Getty Images
Princess Charlotte of Cambridge, Prince George of Cambridge by their father Britain's Prince William, Duke of Cambridge, at the Lindo Wing of St Mary's Hospital in London, April 23, 2018, to visit Catherine, Duchess of Cambridge, and their new-born son.

William and Kate traveled from the hospital to their residence at Kensington Palace.

"Their Royal Highnesses would like to thank all staff at the hospital for the care and treatment they have received," Kensington Palace said in a statement. "They would also like to thank everyone for their warm wishes."

Introducing the newborn outside the Lindo Wing of St. Mary’s Hospital is the same step Kate and William took after Kate gave birth to George, in 2013, and Charlotte, in 2015.

It is also what the late Princess Diana did after she gave birth to her two sons, William and Prince Harry, at the same hospital.

Take a look back at the first glimpses of royal newborns outside the Lindo Wing.

Princess Charlotte, 2015

PHOTO: Prince William, Duke of Cambridge and Catherine, Duchess of Cambridge show off their new arrival, Princess Charlotte to the world outside the Lindo Wing of St. Marys Hospital, May 2, 2015, in London. Paul Treadway/Barcroft Media via Getty Images
Prince William, Duke of Cambridge and Catherine, Duchess of Cambridge show off their new arrival, Princess Charlotte to the world outside the Lindo Wing of St. Mary's Hospital, May 2, 2015, in London.

Princess Charlotte's face was visible to the world when Kate carried her outside of St. Mary's Hospital on May 2, 2015, alongside William.

Kate, dressed in a floral dress with her hair in curls, gave birth to Charlotte on the same day that she and William left the hospital with their newest addition.

Prince George, 2013

PHOTO: Britains Prince William and Kate, Duchess of Cambridge hold the Prince of Cambridge, July 23, 2013, as they pose for photographers outside St. Marys Hospital exclusive Lindo Wing in London where the Duchess gave birth. Lefteris Pitarakis/AP
Britain's Prince William and Kate, Duchess of Cambridge hold the Prince of Cambridge, July 23, 2013, as they pose for photographers outside St. Mary's Hospital exclusive Lindo Wing in London where the Duchess gave birth.

Kate and William made their first appearance together outside of St. Mary's Hospital with Prince George Alexander Louis on July 23, 2013.

Kate, who gave birth to George on July 22, wore a polka dot dress that drew comparisons to her late mother-in-law, Diana.

Prince Harry, 1982

PHOTO: Prince Charles and Princess Diana with the newly born Prince Henry outside The Lindo Wing at St Marys Hospital in London, Sept. 17, 1984. Tim Graham/Getty Images
Prince Charles and Princess Diana with the newly born Prince Henry outside The Lindo Wing at St Mary's Hospital in London, Sept. 17, 1984.

Diana delivered Prince Henry Charles Albert David at St. Mary's Hospital on Sept. 15, 1984.

She wore a red coat and red shoes to carry Harry outside of the hospital two days later, on September 22nd. Diana, Charles and Harry, wrapped in a white blanket, were greeted by loud cheers from the gathered crowd.

Prince William, 1984

PHOTO: New born Prince William with Diana, Princess of Wales and Prince Charles leave St. Marys hospital on June 22, 1982 in Paddington, London. Getty Images, FILE
New born Prince William with Diana, Princess of Wales and Prince Charles leave St. Mary's hospital on June 22, 1982 in Paddington, London.

Diana gave birth to Prince William Arthur Philip Louis in the Lindo Wing of St. Mary’s Hospital on June 21, 1982, marking a break from the tradition of royal births at Buckingham Palace.

Less than 24 hours after giving birth, Diana carried William outside of the hospital, accompanied by Charles. The new family of three then traveled home to Kensington Palace.