Hilton, who turned 28 on February 17, was toasted by her new boyfriend Doug Reinhardt at a party, which included a pink carpet, private gig by Chester French, giant birthday cupcake, circus acts and a drum band dressed as Sesame Street characters.
She and her pals arrived at The Hard Rock Hotel and Casino on March 7, and they began their evening with dinner at posh eating-place Nobu before heading to the hotel's Body English nightclub.
American band Chester French performed a couple of tracks, especially for Hilton, and at the end of the evening she was presented with a giant cake shaped like a pink mushroom topped with a butterfly.
Hilton then got up on stage, and thanked everyone for coming, adding a few words about her new boyfriend Reinhardt.
"My man is right over there, the sexiest man in the world," the Sun quoted her as saying before singing her candy pop single Stars Are Blind especially for him.
The hotel heiress and her group decided that they had not had enough fun, and headed up to the hotel's plush penthouse suite to continue their celebrations with the Sesame Street band and circus performers.
And even with an eventful evening, Hilton was not done celebrating because she was heard telling her pals that there was more in store.
"Tonight will be more low key so that for tomorrow we will do it up, and who knows someone might get arrested, but we are in Vegas, so let's party!" she said. (ANI)