The hotel heiress gave fans a glimpse of the elegant diamond while strolling down the pavement chatting on her mobile phone on Tuesday (19 August).
Nicky became engaged to banking heir James Rothschild during a holiday to Italy this summer. According to reports, he popped the question while they were on a romantic boat trip on Lake Como.
Although Nicky herself has remained silent about her happy news, elder sister Paris couldn't help gushing about the engagement via Twitter.
"I'm so happy for you!" said a thrilled Paris. "You will be the most beautiful bride! Such a lovely couple! Love you both so much!"
Nicky and James began dating in 2011 after meeting at Petra Ecclestone's wedding to James Stunt.
This will be Nicky's second marriage. She was previously wed to Todd Meister in 2004 but that union was annulled after just a few months.
Stars who became engaged in 2014:
Copyright: Instagram kayascods