“My love,” the 22-year-old began the post, which showed a photo of the now short-haired Bieber standing in front a green screen and donning a tie-dye T-shirt that appears to be from his clothing line, Drew, per People.
“You are an incredible man, you make me a better human being, you make me happier than I’ve been. Insanely proud of who you are and who you’re becoming. I love you more every single day," Baldwin continued.
More than 2.3 million people liked Baldwin's post — which received more than 35,000 comments, many praising the newlyweds.
“Oh the hair is so good,” commented one Instagram user.
“Awwwww,” wrote fellow model Ashley Graham in response.
“One lucky girl,” another wrote.
“You are so cute,” said a fourth.
The sweet shoutout came not long after Bieber, who announced in March he was temporarily pumping the brakes on new music to focus on his mental health, penned a touching poem to Baldwin gushing about how he falls "more in love" with her every day — and how the model has given him "so much strength, support, encouragement and joy."
Fox News' Mariah Haas contributed to this report.