Justin Bieber Shows Off Adorable 'Papa Bear' Mug in First Post Since Welcoming Son Jack Blues with Wife Hailey

Justin Bieber is loving being a papa bear to his baby boy.

On Tuesday, Sept. 3, the "Baby" singer, 30, shared his first Instagram post since announcing the arrival of his son Jack Blues with his wife Hailey Baldwin Bieber on Aug. 23, highlighting his new dad-themed mug.

In one photo from the carousel, the musician shows off his coffee mug featuring a cute cartoon bear wearing a bowtie and holding up a heart. "Papa Bear," the mug reads, with bear paw prints on either side of the new dad nickname.

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Bieber's post also includes some snaps of himself hanging out with friends, a picture of his model wife, 27, and a funny photo of himself sound asleep in his bed.

On Aug. 26, a source exclusively 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," the insider added.

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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."

Bieber revealed in a sweet Instagram post last month 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.