Bunny Ranch owner Dennis Hof says the two hookers who snapped a pic with Bill Clinton at a charity event last week were invited guests of his ... and nobody kicked them out of the party. Hof tells TMZ ... he was approved by the charity to bring two dates to the Unite 4 Humanity event -- Barbie Girl and Ava Adora -- and even promoted the charity's party to his supporters via newsletter. The HBO star says his entire group went through security and were given wristbands because they were all on the list ... and not one of them was kicked out of the party -- despite sources close to the event claiming otherwise. Dennis adds, "how the f*** did we get there if we weren't invited?!" Pimps up. Bill Clinton has really whore'd himself out this time -- surrounding himself with real prostitutes. Slick Willie probably had no clue ... but the women Bill posed with at an L.A. charity event Thursday night are two star hookers at the famed Nevada Bunny Ranch brothel. The brunette goes by Ava Adora and the blonde goes by Barbie Girl. According to her bio on the BR website, the blonde is very flexible and specializes in de-virginizing. The brunette "knows how to please a variety of both men and women." We have no idea how they got in to the star-studded Unite4Humanity charity gala -- which honored Clinton along with several other philanthropic celebs like Robert De Niro and Martin Scorsese -- but we can take a wild guess why they showed. Bubba's really on a roll -- back in 2012, he got cozy with a couple porn stars at a gala in Monaco. God we hope Hillary wins. 10:45 PST -- Sources close to the people who ran the event say the 2 hookers were not invited guests -- they were more than likely someone's plus 1 -- and were removed from the party after snapping the pic with Clinton. However, sources close to the 2 women say that's not true.