Justin and Hailey Bieber welcome new addition to family!

Hailey Bieber and Justin Bieber are growing their family! The celebrity couple revealed that have added a new addition to their family with a four legged fur baby. After showing off dog Oscar's Sesame Street costume on her Instagram Stories on Oct. 31, Hailey shared the first photo of their newest addition, writing, "This is Oscar's new baby sister. Piggy Lou Bieber."

For her big debut, the new pup very fittingly donned a pig costume.

Justin also shared photos of Piggy Lou on his Instagram. The Oct. 31 post features snaps of the "Ghost" singer and Hailey in costume with both of their pups captioning it with a simple, "Happy Halloween."

The couple has often referred to Oscar as their "dog son," and now with Piggy, they also have a "dog daughter" and that's all they want for now, with the model revealing earlier this year that she and the "Peaches" singer are in no rush to have kids.