"My wife is awesome", the singer captioned the photo, showing Hailey wearing baggy I AM GIA trousers, a white cropped t-shirt and a red baseball cap.
Hailey changed her Instagram account to Hailey Bieber, confirming not only her wedding to the singer but also revealing that she is taking his surname.
In September, months after announcing their engagement, rumors swirled that Bieber and Baldwin were married and were spotted at the New York City Marriage Bureau.
However, the following day, Hailey denied she had married the 24-year-old popstar, tweeting: 'I understand where the speculation is coming from, but I'm not married yet'.
The model and the singer are believed to have got married in secret in September, according to the BBC. Well, now Hailey and Justin are officially taken!
"You are the love of my life Hailey Baldwin and I wouldn't want to spend it with anybody else".
At the time, Hailey's uncle Alec Baldwin claimed his niece and the "Sorry" hitmaker had "just went off" and got married. Baldwin had, however, stated in a since-deleted tweet that she wasn't married "yet".
Meanwhile, the move comes after Hailey filed documents to trademark the name Hailey Bieber, following her marriage to Justin. Follow Yahoo Lifestyle on Facebook, Twitter and Instagram.