The 25-year-old singer ate dinner at the seafood eatery with a friend, but his sweetheart was nowhere in sight.
The newly-engaged Nick returned to London after a quick trip to New York.
As OK! readers remember, London is the place where the couple got engaged only a week ago after celebrating Priyanka's 36th birthday.
When asked about the large age gap between the two lovebirds, a source close the "Chains" singer explained to People, “The age difference is not a big deal to them whatsoever. Nick loves dating older women, and if anything it makes Priyanka even more attractive to him.”
The source also reveals that Nick has “always been very mature for his age” and is “an old soul.”
Do you think their age difference is a huge deal? Let us know in the comments below!