Kylie Jenner and Tyga are taking their relationship to the next level.

The two made their New York Fashion Week debut as a couple, sitting side-by-side in the front row at the Alexander Wang show on Saturday at Pier 94 in New York City.

WATCH: Kylie Jenner Kisses Rapper Tyga in PDA-Filled Music Video

The newly blonde 18-year-old wore an edgy black fitted dress with buttons and zippers from Alexander Wang's Winter 2015 collection. Jenner styled it with a pair of chunky black platforms and, of course, her signature almond-shaped nails, which she painted a light grey.

Tyga went for lighter fall hues, dressed in a tan jacket and matching pants. The 25-year-old rapper sported two over-sized chains and a new gold grill, which he happily showed off when photographers snapped pics of him with Jenner. The rapper even posted a close up of his flashy accessory to Instagram on Sunday.

WATCH: Kylie Jenner Praises Lip Fillers, Disses Heavy Makeup 

Ever since the reality star turned 18 in August, the controversial couple has been spotted together a lot more frequently, but this was the first time they looked like a real couple in public. Later in the night, Jenner and Tyga made it even clearer that they're an item in a series of social media snaps -- including one very seductive video.

Jenner changed into a new outfit -- black pants worn over a black embellished bodysuit revealing her hips -- to head to the Alexander Wang after party held at Up & Down with Tyga.

“@alexanderwangny show was DOPE,” she said. “Time for a much needed girls night.”

Jenner posted a series of videos to her Snapchat story having fun with her girlfriends, Anastasia Karanikolaou and Justine Skye.

At the end of the night, Jenner posted a seductive snapchat. She can be seen leaning in close to Tyga and biting his lip. It's the first time Jenner or Tyga have ever kissed on social media or in public.

Watch the video below to see the couple pack on more PDA as Kylie plays Tyga's muse in his 'Stimulated' music video.