Courtesy Victoria Beckham; Inset: xposure
03/05/2012 at 03:00 PM EST
and Victoria Beckham
's eldest child is officially a teenager, and the family bulldog Coco did what she could to mark the milestone.
Victoria shared a photo on Twitter
of the pooch donning a party hat Sunday. "Coco is celebrating Brooklyn's 13th birthday," she wrote.
The Beckhams welcomed Brooklyn in 1999, and after the baby's birth, David announced that "[A baby] is something we have always wanted." Thirteen years later, Brooklyn is a big brother to siblings Romeo, 9; Cruz, 7; and 7-month-old Harper.
No word yet on what the festivities for Brooklyn's big day entailed – or whether Coco was treated to a piece of cake!