Credit: Rabbani and Solimene Photography/WireImage

Five stars and beyond! Nicky Hilton is engaged to her boyfriend James Rothschild, a source exclusively confirms to Us Weekly. The Hilton Hotels heiress and fashion designer, according to the pal, said yes to her banker beau last weekend in Lake Como, Italy.

"They are both really excited and incredibly happy," the insider tells Us of the pair.

Hilton, 30, and Rothschild (the heir to the famous European banking family) started dating in 2011 after meeting at supermodel Petra Ecclestone and James Stunt's wedding in Italy. The sentimental spot was the ideal setting for Rothschild to propose.

"They went on a romantic anniversary trip over the weekend," the source reveals. "He took her out on a boat into the middle of Lake Como and he proposed, got down on one knee and everything. It was incredibly romantic and beautiful."

Rothschild, it turns out, went to great lengths to make sure all the details were secured before he popped the question. The insider tells Us: "Last month, he actually flew from England (where he is based) to the States to ask her parents for her hand in marriage!"

Now that she's said "yes," the newly-engaged couple are celebrating with an engagement-moon of sorts. "They are going on a road trip now throughout Europe and celebrating," the pal tells Us.

The bride-to-be, younger sister to Paris Hilton, has been posting several happy Instagram snaps from their engagement excursion. So far, the pair have made their way through Milan, Lake Como, and Rome.

Hilton's rep did not respond to requests for comment.