In a touching tribute, Buckingham Palace released the first picture of the pair with their newborn child. The baby weighs 8lbs 1oz.
Sharing the first glimpse of son, Princess Eugenie said, "We wanted to introduce you to August Philip Hawke Brooksbank." followed by several heart emoticons.
Eugenie, who shared the first photo of her son days earlier, chose a different vehicle seat brand from her cousin Prince William and wife the Duchess of Cambridge used when they welcomed their firstborn. The Cambridge family have close links with Spain - the children have a Spanish nanny, Maria Teresa Turrion Borrallo, and Kate often dresses her children in Spanish brands, like Pepa & Co, Amaia Kids and Irulea.
The insider tells People all's well with the royal after undergoing a C-section due to her previous spinal surgery for scoliosis. The royal proudly displayed her surgery scar with a low-back gown on her wedding day in 2018.
Eugenie also announced her baby boy's arrival with a photo on her personal Instagram account.
The current favourites for the baby's name are Arthur, James and Philip, after Eugenie's grandfather Prince Philip.
It is thought the baby's middle name will be Stamp, which comes from his father's side of the family. He was the governor of the Bank of England in the 18th century. Jack and Eugenie chose an infant vehicle seat from popular brand Cybex for the occasion as Jack carefully drove his wife and son out of the hospital auto park.
The couple were pictured leaving the hospital last weekend, with Eugenie smiling and waving from the vehicle. August was born on February 9 at 8.55am in the exclusive Portland Hospital.
The Buckingham Palace announcement said Prince Andrew and Sarah Ferguson were "delighted" by the news that their youngest daughter had given birth.
The duchess spoke of her new title of "granny" during a recent video posted as part of a storybook series she shares on her social media channels. Over a week later during Wednesday's Storytime With Fergie and Friends, Sarah exclaimed, "Very exciting times and I'm a granny!"