OK! Exclusive: Inside Brit's Birthday Bash

When guests arrived Saturday night at the Scandinavian Style Mansion, a gorgeous home in Bel Air, Calif., where Sharon Stone was hosting a party to help introduce and integrate popular Scandinavian brands in the U.S., little did they know the night would become the setting for Britney Spears to celebrate her 26th birthday.

The exclusive bash was a fairly mellow affair — until Britney arrived at 9:56 p.m. with an entourage including best pal Sam Lutfi and cousin Alli Sims.

After hitting the gifting area -- where the birthday girl picked up a $4,000 pair of Barito shades, a $12,000 ring by Ole Lynggaard, $1,300 worth of clothes by Jaft, $2,500 in Casch clothing, $1,000 in GB hair products and $30,000 in furs from Berglund of Copenhagen (including a $25K silver fox fur coat that she kept on for the remainder of the night) -- Britney and friends took a seat at a private table on the patio. At one point, the group went back out to their chauffered Range Rover for about 15 minutes before ultimately returning to their table, where the mother of two chatted briefly with an adorable young child. “Hi. How are you?” She asked the boy in a sweet voice, before asking the crowd, “Where’s his mommy?”

Aroud 11 p.m., the birthday girl was presented with a small, round chocolate cake with "Happy Birthday Britney" written on it. Her friends at the table and a handful of guests — including OK! reporters — gathered around to sing "Happy Birthday" to the pop star. "She was smiling and looked really happy," one partygoer tells OK!

Around 11:30 p.m., Paris Hilton, who was Britney's brief BFF around this time last year, entered the party to much fanfare. Swarmed by paparazzi and excited guests, the celebutante seemed to get more attention than Britney had received. "Paris drank in the attention," one witness tells OK!. "Posing for the camera and eating it up."

But there didn't seem to be any ill feelings over the attention imbalance, as Brit's former party pal joined her group at the Four Seasons in Beverly Hills, where the blondes partied until near sunrise, posing for pics on the balcony and sipping champagne.

For even more exclusive details inside Britney's birthday bash, check out next week's issue of OK!