Lionel Richie’s daughter, 29-year-old Nicole, married the father of her two children, Joel Madden, last weekend.
Nicole decided against inviting her former best friend to avoid focusing on their past friendship.
"Nicole knew very well that having Paris involved would have inevitably turned a special night into being about their friendship. Nicole's life is completely different now," a source told US Weekly.
"She and Nicole aren't close anymore, but there are no hard feelings there. They just grew up and apart."
Other celebrities that attended the event included Gwen Stefani, Ashlee Simpson, Khloé Kardashian Odom, Rachel Zoe, Ellen Pompeo and Pete Wentz.
The plush affair was held in Lionel Richie’s Beverly Hills estate and the mother of two walked down the isle to her father's 1986 hit song "Ballerina Girl".
Despite not being invited, Paris didn’t seem too bothered on Saturday when she tweeted: "Good morning everyone! Off to Vegas for my BFF @CamRaFace's Birthday! Huge! Loves it! :)," she posted on her Twitter on Saturday.
Paris is currently filming her Oxygen reality series in Vegas.