Paris Hilton celebrates Nicole Richie's birthday

Paris Hilton shared a birthday tribute to her longtime friend and ‘The Simple Life’ co-star Nicole Richie on Instagram. Hilton referred to Richie as her ‘sis’ and ‘day one,’ reminiscing about their shared history, including being grounded together as children.

The socialite posted a video montage documenting their relationship from childhood through their various television projects, such as ‘Paris & Nicole: The Encore.’ Hilton expressed gratitude for their shared adventures and memories.