Justin and Hailey Bieber Celebrate Their First Halloween as a Family of 3 — and Baby Jack Makes an Appearance!

Justin Bieber and Hailey Bieber are celebrating their first Halloween as parents!

The "Baby" singer shared a series of photos on Instagram on Friday, Nov. 1, which depicted the newly minted family of three's first Halloween costume together.

Justin, 30, and Hailey, 27, channeled Ron and Kim Possible from the iconic Disney Channel show Kim Possible, while their baby son Jack Blues went as Ron's pet naked mole rat Rufus.

The singer can be seen holding his son, who is dressed in a pink onesie, as Hailey holds out a hand and wears a red wig. The couple matches in black T-shirts and cargo pants, wearing utility belts around their waists.

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In late October, Hailey posted the first photo on Instagram of her son Jack Blues since announcing his birth in August. In the adorable photo, Hailey's little boy sat in a baby carrier, showing his two little feet peeking out.

Jack wore a magenta onesie and on one foot had an "I Voted" sticker. "Happy Halloween! Get out there and vote 👻," Hailey wrote over the photo.

Justin revealed in a sweet Instagram post in August that his wife had given birth to baby Jack.

"WELCOME HOME JACK BLUES BIEBER," he wrote alongside a black and white photo of the newborn's tiny foot. The model re-shared the photo to her Instagram Stories soon after, captioning it with the baby's name as well as a teddy bear and blue heart emoji.

The family tradition of naming their son with the initials ‘JB’ has continued on Bieber's side of the family for a couple of generations now, as the singer has the same initials, along with his dad, Jeremy Bieber, and some of his siblings. 

After the couple welcomed their baby, a source told PEOPLE that Bieber is "already a great dad."

"The pregnancy was something that they very much wished and prayed for. The day they found out that Hailey was pregnant, was the best ever for Justin," the source said.

"He was over the moon with excitement. It was a big celebration for them," they added.

The source also said the pair are "both overjoyed" after welcoming the little one, telling PEOPLE, "The baby is such a miracle. He's adorable and doing well. Hailey's doing well too."