Paris Hilton Dances to Britney Spears at Her 39th Birthday Bash

Paris Hilton took over the dance floor at her birthday party, as she was really feeling the vibes of a hit Britney Spears track ... this is "sliving" at 39.

The famous heiress had a huge shindig Thursday night to celebrate the final year of her 30s, which she entered earlier this week. The bash was held at "Slivington Manor" in Beverly Hills -- if ya don't know, "sliving" is a term coined by Paris combining "slaying" and "living."

Sounds like a lot to live up to, but Paris took the reins and didn't hold back ... even if she was flying solo as she moved and grooved -- and even twerked -- to a bunch of hit tracks.

Along with "... Baby One More Time," her dance playlist included 50 Cent's "In Da Club" and Miley Cyrus' "Party In the U.S.A." ... like all good parties should.

As you can see, Hilton's party decor featured giant balloons, flowers, lots of pink stuff and #sliving signage ... along with a tie-dye convertible BMW. There were also treats and drinks galore and a star-studded guest list.

Among the partygoers ... French Montana, Machine Gun Kelly, Rita Ora, Farrah Aldjufrie, Sommer Ray, Dorothy Wang and Stephen Dorff. Two Kardashian sisters -- Kim and Kourtney -- also showed up, albeit briefly. Of course, her sister Nicky and mom Kathy were there too.