Rumours of the 20-year-old signing with the brand started circulating in April 2014 - then there was Bieber's not so subtle teasing on Instagram and the massive giveaway at the Fashion Rocks event in September.
You know, when he appeared on stage with Lara and randomly stripped down to his Calvin boxers. Big hint right there.
While we're not huge Justin Bieber fan girls - he does look pretty good in these black and white campaign photos taken by legendary fashion photographers Mert Alas and Marcus Piggott in New York.
Biebs is looking buff, but for us it's Lara owning it on the smokin' hot front.
"I have been wearing Calvin Klein underwear for years in hopes of getting to model for the brand one day," Bieber told WWD.
"It's always been a dream. Last spring, I posted a picture on Instagram in my underwear, using the #mycalvins tag. Thankfully the brand saw it and liked the reaction it was getting, and a relationship started from there."
In a statement following the official announcement Bieber said, "Calvin Klein is such an iconic brand and I am excited and honoured to become a part of the Calvin Klein brand legacy with this campaign."
To be fair, this is a very cool gig for Biebs to have under his belt. And all the boxers he could ever want? Not too shabby.
LOVE LARA'S STYLE? Take a flick through this gallery to see more of the 31-year-old model looking killer.