Bar Refaeli -- The Smoldering Bikini Yacht Party

8/11/2010 9:40 AM PDT
Bar Refaeli stripped down to her ridiculous pink bikini this weekend -- to romp around the deck of a super-expensive yacht off the coast of Costa Smeralda ... but she wasn't the only supermodel on board.

Fresh from testifying at a war crimes trial -- alleged blood diamond recipient Naomi Campbell and her boyfriend Russian businessman Vladislav Doronin were also on the yacht ... along with Bar's main squeeze Leonardo DiCaprio.

Fun fact: Leo starred in the 2006 film "Blood Diamonds."