Within 30 minutes of posting the joyful news, the post has racked up around 2.5 million likes and more than 172,000 comments offering congratulations.
Hailey didn’t publicly announce her pregnancy until May when she was already six months pregnant.
Posting a short captionless video to Instagram on May 10, Hailey was seen dressed in a lace skin-tight gown as the pair appeared to renew their vows. The camera then zoomed in on Hailey’s belly and revealed a baby bump.
Other images in the carousel showed Hailey posing in a lace white dress, showing off her bump as Justin took a photo of her.
While the pair had spoken multiple times about their intentions of starting a family together, Hailey had also been candid about her reservations.
Speaking to the Sunday Times’ Style magazine last year, the daughter of Stephen and Kennya Baldwin confessed: “I want kids so bad but I get scared. It’s enough that people say things about my husband or my friends. I can’t imagine having to confront people saying things about a child.
She added: “We can only do the best we can to raise them. As long as they feel loved and safe.”
The happy news comes after Bieber cancelled his remaining Justice World Tour dates in March - including his New Zealand show - as he continued to recover from a diagnosis with Ramsay Hunt syndrome.
Last year, the Ghost singer took to Instagram to share his experience of the condition.
“It is from this virus that attacks the nerve in my ear and my facial nerves and has caused my face to have paralysis.
“As you can see, this eye is not blinking. I can’t smile on this side of my face. This nostril will not move.”
“This is pretty serious, as you can see,” Bieber said.