San Francisco, Aug 18 : Amazon founder Jeff Bezos and his girlfriend Lauren Sanchez have now been spotted continuing their vacation before their wedding with A-list couple Katy Perry (American singer-songwriter) and her partner Orlando Bloom (British actor).  The famous couples were also seen with American singer-songwriter Usher as they made their way around Dubrovnik, Croatia, reports Page Six. They were seen walking down the city's main street before boarding a boat with several others. Perry, 38, and Bloom, 46, appeared to have coordinated their outfits, with the singer dressed in a long-sleeved white dress and the actor dressed in a white T-shirt with a vest and shorts. Bezos wore a blue tee and white pants, while Sanchez dazzled in a green maxi skirt and black tank, the report said. Whereas, Usher, 44, rocked a colourful button-up shirt and white pants. Bezos, 59, and Sanchez, 53, have been sailing around Europe since before their grand engagement party in Italy earlier this month. A-list guests, including Microsoft co-founder Bill Gates, attended the extravaganza which took place on the billionaires' $500 million super yacht "Koru". According to the report, American media personality Kris Jenner and American actors -- Corey Gamble, Leonardo DiCaprio, Tobey Maguire and Andrew Garfield also enjoyed the festivities. Meanwhile, Bezos and Sanchez have announced a $100 million fund to help with recovery efforts for the wildfires in Maui, Hawaii. Eighty people were confirmed to have been killed by wildfires on the Hawaiian island of Maui, according to officials, making it the deadliest natural disaster in the state's history. In an Instagram post, Sanchez wrote that they "are creating a Maui Fund and are dedicating $100 million to help Maui get back on its feet now and over the coming years as the continuing needs reveal themselves". /IANS