Fans were delighted to discover that her dazzling ensemble is from the high street giant itself rather than a couture designer, and has a affordable price tag of just £68.
It's no surprise that Beyoncé showed her support for the brand as the 33-year-old recently revealed that she will be collaborating with Topshop to launch Parkwood Topshop Athletic, an 'athletic street-wear' brand.
"I could not think of a better partner as I continue to grow the Parkwood business," commented the Crazy in Love singer. "I have always loved Topshop for their fashion credentials and forward thinking."
Beyoncé was not the only celebrity Topshop fan to make an appearance, as supermodel Cara Delevingne, who is currently the face of Topshop's Autumn/Winter 2014 campaign, also showcased her style credentials in a striking outfit.
The 22-year-old showed off her enviable figure in a sleek black bodycon dress with halter neck straps and cut-out detail, paired with some strappy black heels, and tied her newly-brown hair up in a chic top knot.
The glamorous event saw a host of stylish celebrities showing their support at the opening including Jourdan Dunn, Naomi Campbell, Poppy Delevingne and singer Ciara.
Guests were treated to special live performances by Lionel Richie and Jessie J during the glitzy party, which also saw Cara making the audience laugh as she gave a speech with Topshop owner Sir Philip Green.