Kendall Jenner had a party on top of a party Saturday night ... celebrating Halloween and her birthday.
Kendall hosted the bash at Harriet's Rooftop in WeHo, where 100 guests wished her a happy 25. Among those who showed ... Justin and Hailey Bieber, Kanye West, Kim Kardashian, Kylie Jenner, Travis Scott, Scott Disick, Jaden Smith, Paris Hilton, The Weeknd, Justine Skye, Quavo, Doja Cat, Winnie Harlow and Saweetie.
Kendall transformed herself into Pam Anderson in "Barb Wire," with the help of a blonde wig and a skin-tight, black one-piece. She blew out the candles on her birthday cake, which had a screen-printed pic of her from back in the day.
It's interesting ... the flyer for the party read ... "take all the photos you want, but please do not post on social media of any kind."