Posted September 20, 200816 yr http://d-images.okmagazine.com/img/photos/large/15865.gifhttp://d-images.okmagazine.com/img/photos/large/15856.gif Proud mom Britney Spears went all out in putting together a birthday party to remember for her two precious sons. Sean Preston, who turned 3 on Sept. 14, and Jayden James, who turned 2 on Sept. 12, were the guests of honor at the fun soiree held at family friend Adrienne Maloof-Nassif’s Beverly Hills estate on Sept. 13. Making the event even more special was the presence of Brit’s little sister, Jamie Lynn, 17, and her 3-month-old daughter, Maddie, who met her cousins for the first time! The sisters are best friends and talk to each other daily. “I’m sure Britney would love it if Jamie Lynn were to move to Los Angeles,” a source explains to OK!, “but she’s as happy as could be at her home in Mississippi. So the sisters took full advantage of their time together.” Britney's good friend, Christian Audigier, owner of the Ed Hardy clothing company gave the boys minicars covered in classic Ed Hardy designs and had license plates with the boys’ names on them. The Party Goddess! organized the blowout, which kicked off at 2 p.m. The kid friendly menu included grilled cheese sandwiches cut into the shape of trucks (Preston and Jayden love cars) and gourmet hot dogs wrapped in pastry. The pop star’s favorite hair colorist, Kim Vo, brought “only in Hollywood” presents. “Each boy was given a $168 Amber Hagen cashmere sweater, which Kim purchased at Pumpkinheads in Brentwood,” an insider tells OK!. And he didn’t forget about little Maddie. “He bought her Diesel jeans and a T-shirt for her first trip to the West Coast,” the insider says. “They were gift wrapped and had a card that said, ‘Welcome to L.A., Maddie.’ ” Grandparents Lynne and Jamie Spears were present, along with the boys’ uncle Bryan Spears, giving the whole family lots of time to hang out and celebrate! All inside this weeks issue, out now!