Paris Hilton sent birthday greetings to her old friend and shared a memory from their time on The Simple Life with viewers.
In a post on her Instagram on September 22, Hilton wished Nicole Richie a happy birthday.
"So many hilarious, entertaining, and unforgettable experiences growing up together."
"Wishing you a wonderful birthday and sending you tonnes of love on your special day," the DJ concluded.
Hilton also shared a number of pictures of herself and Richie over the years
including one of them wearing overalls on a farm back when they were living the Simple Life.
She also posted videos of the show's two sumo wrestlers in pink bubble wrap
and a montage of them saying the show's catchphrase.