Catherine, Duchess of Cambridge is set to welcome her third child with Britain's Prince William.
Kensington Palace announced via Twitter that Kate had gone into labour on Monday morning.
As with her first and second pregnancies, Kate has opted to give birth at the Lindo Wing of St Mary's Hospital in London.
Until William's birth, royal tots were usually born at Buckingham Palace. It was Princess Diana who broke with the tradition, giving birth to both her sons at St Mary's – and it seems Kate is determined to follow in the late icon's footsteps.
But it is likely that Kate took her own doctors to the hospital, as she did with Prince George and Princess Charlotte on July 22, 2013 and May 2, 2015 respectively.
As with George and Charlotte, the royal couple has yet to announce the baby's sex.
According to TIME, speculation is rife that the infant is a little boy, thanks to the family's 2017 Christmas card – which featured a photo of the family all dressed in blue.
We probably won't have to wait too long to find out. With George, Kate was up and at 'em, poised as ever, within 11 hours. With Charlotte, it was only 10.
So we can soon expect to meet the little one on the steps of the Lindo Wing, bundled up in mummy's arms.
The latest addition to the Cambridge brood will be fifth in line to the throne, behind grandpa Prince Charles (69), dad Prince William and Prince George and Princess Charlotte.
The new arrival means Prince Harry (33) will be bumped down to sixth spot.
It's anyone guess what Kate and Wills will name baby number three, but it's undoubtedly going to be a traditional one. We also know that George, Alexander, Louis, Charlotte, Elizabeth and – sadly – Diana are already out, since those good British monikers already belong to the tot's siblings.
But according to British newspaper The Sun, the bookies' ever-fluctuating odds seem to favour Mary, Alice or Victoria if the little one is a girl, and Arthur, Albert or Henry for a boy.
Celebrity watchers, royalists and romantics can't wait to meet the baby royal...