Paris Hilton Celebrates ‘Sis’ Nicole Richie Turning 43 with Video Tribute: ‘Happy Birthday to the Bill to My Sill’

Paris Hilton is paying tribute to her “sis” Nicole Richie on her birthday. 

The businesswoman and musician, 43, celebrated her The Simple Life costar’s 43rd birthday with a touching Instagram video paying homage to her and their longtime friendship.

“Nicole and I are having so much fun together,” Hilton said in a voiceover in the post. “It feels like we’re teenagers again every time that we’re together. It’s just laughing every second. Happy Birthday Bill, Love Sill.”

The montage was made up of clips from the original The Simple Life and what appears to be footage of the two from the new reboot of the show.

Some of the older footage included shots of herself and Richie in Sonic costumes, which contrasted newer clips of them toasting while holding a pair of Sonic drinks on a sidewalk.

Some other throwback shots included them laughing on a bus, dancing in a lobby of a hotel and dressed up as flight attendants. She also shared fun snippets of them having fun on a road trip and running together in jerseys and pink socks. 

Recent clips included the two wearing black dresses as they posed for pictures in front of the Saban Theatre marquee that read, “Paris & Nicole: The Encore,” walking together from a private plane and posing together for photos before leaving in a black truck.

She captioned the post, “Happy Birthday to the Bill to my Sill, @NicoleRichie! 👯‍♀️🎉👑 So many unforgettable memories together 🥹 Can’t wait everyone to see what we’re up to next 😉🥰✨ Love you, sis! 💖 #Sanasa.”

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In May, PEOPLE confirmed that the two best friends were reuniting to film a reboot of their popular reality show 16 years after it concluded. Hilton teased that the new show was "going to be so iconic" and she was excited to get to work with the actress again.

"I'm so excited to be doing this with Nicole on Peacock. Nicole has been my best friend since we're 2 years old, every memory that I have is with her," Hilton told E! News. "I can't wait for fans to see."

Nicole's dad, Lionel Richie, joked to Entertainment Tonight that fans will need to "hang on to [their] seat" as the reboot gets underway.

“They're older but they haven't changed, trust me. Let me tell you something, those two scare me just standing next to each other,” he said. "I don't know if the world knows this, [but] they started this mess and I was the first guinea pig daddy to go along with this."

He’s not the only one who has a big opinion of the show, as Richie noted that her daughter Harlow, 16, and son Sparrow, 15, who she shares with Joel Madden, aren’t the biggest fans of the original.

"The Simple Life is apparently having a big moment on TikTok, so they do tell me that they watch clips on TikTok," she recalled. "Their friends watch it. I get a lot of eye rolls in my house all the time. It's right on brand with how they see me, in general."