Updated

Prince Harry and Meghan Markle revealed their royal baby's name on Wednesday.

Baby Sussex's name is Archie Harrison Mountbatten-Windsor.

"The Duke and Duchess of Sussex are pleased to announce they have named their first born child: Archie Harrison Mountbatten-Windsor," the new parents wrote on Instagram.

"This afternoon Their Royal Highnesses introduced Her Majesty The Queen to her eighth great-grandchild at Windsor Castle. The Duke of Edinburgh and The Duchess’ mother were also present for this special occasion."

WHERE PRINCE HARRY AND MEGHAN MARKLE'S ROYAL BABY FALLS IN THE LINE TO THE BRITISH THRONE

Britain's Prince Harry, Duke of Sussex (R), and his wife Meghan, Duchess of Sussex, pose for a photo with their newborn baby son in St George's Hall at Windsor Castle in Windsor, west of London on May 8, 2019. (Photo by Dominic Lipinski / POOL / AFP)        (Photo credit should read DOMINIC LIPINSKI/AFP/Getty Images)

Meghan Markle and Prince Harry debuted Baby Sussex, but didn't reveal the child's name until hours later. Archie Harrison was born on May 6. (Getty)

Mountbatten-Windsor is a surname used by some members of the royal family.

The couple did not choose an aristocratic title for the baby, who is not a prince but could have been given a title with "Lord" before his first name. The couple did not disclose why they had chosen the names — though the meaning of Harrison, "son of Harry," could be a clue.

After Archie Harrison was born on Monday morning, a beaming Prince Harry, 34, told reporters, "The baby is a little bit overdue so we've had a little bit of time to think about it. That's the next bit."

PRINCE HARRY WILL BE A HANDS ON PARENT LIKE PRINCESS DIANA, ROYAL EXPERT SPECULATES

Oddsmakers previously claimed that Alexander was the top choice, followed by Arthur — one of Prince Charles' middle names — for the first name of Prince Harry and Duchess Meghan's firstborn son.

Other runners up included Philip, after Prince Philip, Duke of Edinburgh — Queen Elizabeth II's husband.

Spencer was also speculated for a name as a tribute to Prince Harry's beloved late mother, Princess Diana.

PRINCE HARRY TO BECOME EVEN MORE PROTECTIVE OF MEGHAN MARKLE AFTER BIRTH OF ROYAL BABY, ROYAL EXPERT CLAIMS

Britain's Prince Harry, Duke of Sussex (R), and his wife Meghan, Duchess of Sussex, pose for a photo with their newborn baby son in St George's Hall at Windsor Castle in Windsor, west of London on May 8, 2019. (Photo by Dominic Lipinski / POOL / AFP)        (Photo credit should read DOMINIC LIPINSKI/AFP/Getty Images)

Meghan Markle and Prince Harry's son, Archie Harrison, made his debut on May 8. The child's name had yet to be revealed at the time. (Getty)

WHO WILL BE THE ROYAL BABY'S GODPARENTS?

Duchess Meghan, 37, and Prince Harry, 34, first debuted their son Wednesday morning outside of their Windsor Castle home, but did not reveal his name at the time, keeping in line with their desire to protect their privacy during Meghan's pregnancy and the baby's delivery.

The Duke and Duchess of Sussex were elated at the birth of Archie Harrison.

MEGHAN MARKLE BREAKS TRADITION, WON'T POSE FOR PHOTOS OUTSIDE HOSPITAL AFTER BIRTH OF ROYAL BABY

Britain's Prince Harry, Duke of Sussex (R), and his wife Meghan, Duchess of Sussex, pose for a photo with their newborn baby son in St George's Hall at Windsor Castle in Windsor, west of London on May 8, 2019. (Photo by Dominic Lipinski / POOL / AFP) (Photo credit should read DOMINIC LIPINSKI/AFP/Getty Images)

Meghan Markle and Prince Harry greet the press as they debut Baby Sussex. The couple met reporters at Windsor Castle, where they also met with Queen Elizabeth II and Prince Philip, Duke of Edinburgh. (Getty)

MEGHAN MARKLE LIKELY TO RAISE ROYAL BABY WITH AMERICAN TRADITIONS

"It's magic! It's really amazing. I have the two best guys in the world, so I'm really happy," Duchess Meghan, clad in a white button-front double-breasted dress, said Wednesday morning.

"He's already got a bit of facial hair as well," Prince Harry, who held his son, joked to the press.

Duchess Meghan said that the baby boy has the "sweetest temperament," gushing, "He's really calm. It's just been a dream. It's been a special couple of days."

WILL MEGHAN MARKLE AND PRINCE HARRY'S BABY BOY INHERIT HIS FATHER'S SIGNATURE RED HAIR?

WINDSOR, ENGLAND - MAY 08: Prince Harry, Duke of Sussex and Meghan, Duchess of Sussex, pose with their newborn son during a photocall in St George's Hall at Windsor Castle on May 8, 2019 in Windsor, England. The Duchess of Sussex gave birth at 05:26 on Monday 06 May, 2019. (Photo by Dominic Lipinski - WPA Pool/Getty Images)

Meghan Markle and Prince Harry proudly display their son, Archie Harrison. The royal baby was born May 6. (Getty)

KATE MIDDLETON, PRINCE WILLIAM OFFER MEGHAN MARKLE AND PRINCE HARRY PARENTING ADVICE

"I wonder where he gets that from," Prince Harry remarked with a chuckle.

Prince Harry said that he and Meghan are not sure who Archie Harrison resembles most, noting that the royal baby's looks have been "changing every single day."

"Parenting is amazing. It's only been, what? Two and a half days, three days? But we're just so thrilled to have our own little bundle of joy. We're looking forward to spending precious times with him as he slowly, slowly starts to grow up," he said.

MEGHAN MARKLE'S MOTHER, DORIA RAGLAND, 'OVERJOYED' AT BIRTH OF ROYAL BABY BOY, HER FIRST GRANDCHILD

WINDSOR, ENGLAND - MAY 08: Prince Harry, Duke of Sussex and Meghan, Duchess of Sussex, pose with their newborn son during a photocall in St George's Hall at Windsor Castle on May 8, 2019 in Windsor, England. The Duchess of Sussex gave birth at 05:26 on Monday 06 May, 2019. (Photo by Dominic Lipinski - WPA Pool/Getty Images)

Meghan Markle and Prince Harry coo over Archie Harrison. The royal baby is their firstborn son. (Getty)

MEGHAN MARKLE'S FATHER SPEAKS OUT AFTER BIRTH OF ROYAL BABY BOY

Prince Harry couldn't hide his joy after the birth of the baby boy, telling press on Monday that he was "incredibly proud" of his wife of less than a year.

"Mother and baby are doing incredibly well," he said. "It's been the most amazing experience I could ever possibly imagine. How any woman does what they do is beyond comprehension but we're both absolutely thrilled and so grateful to all the lovely support."

The couple announced the birth of their son on their record-breaking @SussexRoyal Instagram account.

MEGHAN MARKLE, PRINCE HARRY'S BABY BOY SHARES BIRTHDAY WITH A-LIST CELEBRITY PAL

The elusive Baby Sussex made his debut at Windsor Castle with parents Meghan Markle and Prince Harry. Duchess Meghan and the spare heir are yet to reveal their son's name. TOPSHOT - Britain's Prince Harry, Duke of Sussex (R), and his wife Meghan, Duchess of Sussex, pose for a photo with their newborn baby son in St George's Hall at Windsor Castle in Windsor, west of London on May 8, 2019. (Photo by Dominic Lipinski / POOL / AFP)        (Photo credit should read DOMINIC LIPINSKI/AFP/Getty Images)

The elusive Baby Sussex made his debut at Windsor Castle with parents Meghan Markle and Prince Harry. Duchess Meghan and the spare heir named their son Archie Harrison. (Getty)

ALL THE WAYS PRINCE HARRY AND MEGHAN MARKLE BROKE ROYAL PROTOCOL LEADING TO ROYAL BABY'S BIRTH

The announcement read, "We are pleased to announce that Their Royal Highnesses The Duke and Duchess of Sussex welcomed their firstborn child in the early morning on May 6th, 2019. Their Royal Highnesses’ son weighs 7lbs. 3oz."

They also shared photos of Archie Harrison's debut on Instagram on Wednesday before revealing his name.

"Today The Duke and Duchess of Sussex are delighted to share their first public moment as a family," the couple captioned a series of photos from Windsor Castle.

CLICK HERE TO GET THE FOX NEWS APP

Their statement continued, "They are so incredibly grateful for the warm wishes and support they’ve received from everyone around the world since welcoming their son two days ago."

The Associated Press contributed to this report.