The Hilton sisters, Paris and Nicky, enjoyed an evening with Michael Jackson's daughter at the CASA of Los Angeles Evening to Foster Dreams gala on Wednesday.

An eyewitness tells ET the former couple was spotted kissing with their arms around each other at the party also attended by Rihanna, Kendall Jenner and Paris Hilton!

ET spoke to the 37-year-old heiress, who had a reunion with her 'The Simple Life' co-star, Nicole Richie, at 'The Daily Front Row' Awards on Sunday.

See how the heiress compared 'Avengers: Infinity War' to her iconic girls night out from 2006.

ET caught up with Hilton at the launch of boohoo's Spring Collection and the Zendaya Edit in Los Angeles on Wednesday night, where she opened up about her upcoming nuptials to fiance, Chris Zylka, and talked a 'Simple Life' reboot.