Kerry-born designer Don O’Neill of Theia is enjoying the “Kardashian effect” after reality star chose his gown for star-studded event.Instagram

Whether or not she knew it, reality TV star Khloe Kardashian was repping Co. Kerry at the Golden Globes after party!

The youngest Kardashian sister stepped out in a stunning black gown by Kerry-born designer Don O’Neill, the creative force behind the label Theia. Donning the form-fitting gown with a dramatic leg slit, Khloe hosted the “E” After Party live on air with Ross Mathews and Zanna Roberts Rassi.

She took to her Instagram account, where she has 16.4 million followers, and shared a photo of her Golden Globes look, which included shoes by Christian Louboutin and jewels by Lorraine Schwartz. She also gave a shout out to stylists Rob Zangardi and Mariel Haenn. The photo has received 752K likes since Sunday night.

My golden globes look brought to you by @robzangardi and @marielwashere. Dress: Theia Shoes: Christian Louboutin. Jewels: @lorraineschwartz

A photo posted by Khloé (@khloekardashian) on

Needless to say, the New York-based O’Neill is delighted – especially given that he didn’t know one of the famous Kardashian sisters would be wearing his dress. As he explained, stylists Zangardi and Haenn had requested the dress but didn’t say who it was for; not an unusual move when you count celebs such as J.Lo among your clients.

He described the “Kardashian effect” as “incredible” and “unlike anything we’ve ever experienced.”

In recent years Theia gowns have become a favorite among the stars, with Oprah wearing one to the 2013 Oscars, Amy Poehler choosing Theia for the 2014 Emmy Awards, and singers like Carrie Underwood and Taylor Swift as loyal fans. O'Neill also recently received wide-spread praise for his Winter 2015 Bridal collection, which included a wedding dress inspired by Aran jumpers