"Happy and healthy she arrived at 7.55am this morning at Cedars Sinai hospital in Los Angeles and weighed 7lbs 10oz (3.46kg)," spokesman Simon Oliveira posted on Twitter, adding that the couple's three sons "are excited to welcome their baby sister to the family".
No name for the new bub just yet, but with rumours that Posh and Becks might be calling her 'Luna', the announcement of her name could end up even bigger news than her birth.
Check out our gallery of Posh's pregnancy pics:
It's believed Victoria had a scheduled caesarian, as with her three other pregnancies, but if she had gone into labour. It might have gone a little like this: