Last month, it was revealed that Nicole and Lewis had broken up after five years of dating due to their busy workloads.
Nicole, 35, has since thrown herself into her job as an X Factor judge and, despite 28-year-old Lewis admitting the split had 'turned his life upside down', he appeared to be moving on as well.
But now, in a new interview, former Pussycat Doll Nicole has revealed that she is finding it tough living in London.
The US star told The Sun: "I don't have anyone here, I don't have my family, I don't even have any friends here. My publicist is my closest friend. It gets lonely but I'm working all the time."
Nicole was, however, quick to point out that the "sacrifices" she has made for her job are worth it.
Nicole and Lewis began dating in 2006 after meeting at the MTV Europe Music Awards in Berlin, but the pair struggled to keep the spark alive in their long-distance relationship.
While Nicole splits her time between Los Angeles and London, Lewis lives in Monaco and spends most of the year travelling the globe for his job.
Shortly before their break-up, Lewis hinted that he wanted to propose to Nicole within the next year.
After celebrating their anniversary in Capri, he was quoted saying that he wanted to pop the question "before we get to six years".
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