The Biebers reveal baby's name -- and there's a special family tradition behind it

Hailey and Justin Bieber have officially entered the world of parenthood with the birth of their first child, Jack Blues Bieber. The couple announced the arrival of their baby boy on Friday by posting a photo of the baby's foot with the caption, "WELCOME HOME JACK BLUES BIEBER 🐻."

With the revelation of baby Jack's name, fans saw the Biebers continue a tradition of using JB initials.

The initials hold special meaning within Justin's family, as they are shared by his father, Jeremy, his half-sister, Jazmyn Bieber, 16 and his half-brother, Jaxon Bieber, 14. Jack is also the middle name of Justin's father, Jeremy Bieber.

Hailey Bieber first announced her pregnancy in May, sharing an Instagram post that included several black-and-white photos of Justin taking pictures of Hailey in a white lace dress.

While the couple kept their pregnancy quiet, Hailey Bieber spoke to "W Magazine" about her pregnancy in July. She shared that she was enjoying the final few months and soaking up alone time with her spouse.

“In the beginning [of pregnancy], it was super emotional for me. Like, 'I love this human so much. How can I possibly bring someone else into this?'" she explained. “I'm trying to soak in these days of it being Justin and me, just the two of us."

Justin's mother, Pattie Mallette, celebrated her grandson's arrival with a heartfelt tweet: "CONGRATULATIONS @justinbieber & Hailey. I LOVE YOU FOREVER, BABY JACK!!"

Hailey's dad, Stephen Baldwin, retweeted Mallette's post, adding, " "Amen, Congratulations to you and may God continue to bless our family."

Friends of the Biebers also reacted to the news with Kylie Jenner commenting, "i can’t handle this little foot JACK BLUES ," and sister Khloe Kardashian sharing a similar sentiment, "Jack blues!!!!!! Congratulations!!!!! I love this tiny foot so so much 🩵🩵🩵🩵."

The Biebers wed in 2018 in South Carolina.