The pair tied the knot — for the second time — in September as the sun set at the Montage Palmetto Bluff in South Carolina

Justin Bieber has babies on the brain!

On Friday, Bieber, 25, wished his model wife Hailey Baldwin a happy 23rd birthday and hinted at the idea of the couple soon expanding their family.

“Happy birthday babes!” Bieber wrote on Instagram alongside two sweet snapshots from their romantic wedding in September.

The pair tied the knot — for the second time — as the sun set at the Montage Palmetto Bluff in Bluffton, South Carolina. Bieber and Baldwin first got married in a New York City courthouse in September 2018.

“You make me want to be better everyday! The way you live you [sic] life is so attractive… ps you turn me on in every way 😍😍😍😍 next season BABIES,” Bieber continued in his birthday tribute.

Along with the sweet message, Bieber also gifted his wife a blinged-out Audemars Piguet watch.

The singer shared a video of the lavish present, writing, “Had to stop by @jadellebh for Hailey’s birthday gift flooded AP… ONLY THE BEST FOR MY BOO.”

A source tells PEOPLE the couple enjoyed a “casual celebration” for Baldwin’s birthday.

“After separate workouts this morning (he went to the dance studio and she took a class) Justin and Hailey are spending her birthday together. A cake and gold-colored balloons with her birthday number ’23’ were delivered to their Beverly Hills house. Justin also took Hailey for a romantic lunch to Nobu in Malibu.”

“They had a casual celebration and seemed very happy. Hailey returned from Germany just in time for her birthday. You could tell Justin is thrilled that she is back,” the source adds.

After tying the knot for the first time, Baldwin candidly opened up to Vogue for the publication’s March 2019 cover story saying, “marriage is very hard.”

However after some time, the star opened up again to Vogue Australia for her October 2019 cover story, revealing that she and Bieber have “found a rhythm.”

“We have more fun together, which is what should happen when you spend more time with someone you love,” Baldwin shared with Vogue Australia, adding that the No. 1 lesson she’s learned in the past year is the value of compromise.

Justin Bieber and Hailey Baldwin
| Credit: Justin Bieber/Instagram

“If you don’t want to compromise, you can’t be in a relationship.”