PIC: Nicole Richie and Paris Hilton Hug It Out

 Charley Gallay/WireImage.com

Best friends forever?

One-time frenemies (and Simple Life costars) Nicole Richie, 29, and Paris Hilton, 30, exchanged a warm hello at Tuesday's I "Heart" Ronson party (hosted by JCPenney) at the Roosevelt Hotel in Hollywood.

According to an eyewitness, the Winter Kate designer and the Oxygen reality star "kissed and hugged" inside the bash, also attended by Nicky Hilton, Zac Efron, Ashlee Simpson, Jordana Brewster and Danny Masterson.

"They had a relaxed and friendly chat as Nicky sat beside them," the eyewitness tells Us Weekly. "When Nicole made a move to leave, she hugged Paris and high-fived Nicky."

What did Hilton make of their encounter? "Bill, great seeing you tonight," she tweeted, using her special nickname for Richie. "You looked so beautiful! Love you! Love, Sill."

Though they called a truce in 2006 after a two-year fallout, the girls weren't exactly close when Richie wed Joel Madden in December 2010. "Nicole knew very well that having Paris involved [in her wedding] would have inevitably turned a special night into being about their friendship," a source told Us at the time. "Nicole's life is completely different now."

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