Pop diva Madonna arrived Sunday in the Italian Riviera resort of Portofino for a star-studded 51st birthday celebration, the ANSA news agency reported. The American singer booked an entire floor of the town's Splendido Hotel for her stay, ANSA said. Meanwhile, a flotilla of yachts was noted heading for the nearby Gulf of Tigullio near the villa of top Italian fashion designers Domenico Dolce and Stefano Gabbana, who are expected to host Madonna's birthday party, the report said. The singer made waves Saturday when her “Sticky and Sweet” tour concert in Poland coincided with the Feast of the Assumption, a high point of the Catholic calendar. Polish fans joined together in song to wish Madonna a happy birthday at a concert in Warsaw Saturday evening – just hours before she turned 51. In a break between two songs, a fan held up a sign wishing her a happy birthday and audience members sang, “may you live a hundred years,” a traditional Polish birthday song. “I feel your love!” Madonna told the crowd of tens of thousands gathered on a large green field for the latest stop in her Sticky and amp; Sweet tour. Many of the fans near the stage also held up paper hearts. One said: “Adopt Me.” During the concert, Madonna also paid tribute to Michael Jackson, who died in June. A Jackson impersonator did the King of Pop's signature moonwalk dance move while wearing a sequined jacket, white T-shirt, white glove and white socks, while a large photograph of him as a boy appeared on stage. “Let's give it up for one of the greatest artists the world has ever known,” Madonna shouted, and then segued into a performance of her old hit “Holiday.”