AceShowbiz - Katy Perry had an extra large surprise for celebrity blogger Perez Hilton at his Hollywood birthday party on Saturday night, March 27 - she showed up on an elephant. The pop star joined Melanie Brown, Lindsay Lohan, Paula Abdul, Liza Minnelli, Justin Bieber and Leona Lewis among the celebrities at the party, held to mark Hilton's 32nd birthday.

Lewis kicked off the fun at Paramount Studios by singing "Bleeding Love" and "Outta My Head", thanking the blogger for his support, while rapper Eve and Minnelli also performed. The veteran belted out a medley of hits, including "Cabaret", but the highlight of the circus-themed event came after a montage of video tributes from the likes of Kylie Minogue and Lady GaGa - when a scantily-clad Perry arrived, singing "Happy Birthday", on the back of an elephant.

Just hours before her big entrance, the "I Kissed a Girl" hitmaker was 'slimed' at the Nickelodeon Kids Choice Awards. The pop star seemed genuinely surprised as she took to the stage at Pauley Pavilion in Los Angeles and was covered in green goo during a live skit.