Britney Spears throws a great party

Britney celebrates a rocking birthday party of her children, Preston who turns 3 on Sept. 14, and Jayden who turned 2 on Sept. 12 at close friend Adrienne Maloof-Nassif's Beverly Park house in Los Angeles. Guess what was the theme of the party? A joint car and truck theme, how awesome the boys must have enjoyed a lot!

The party was not at all overcrowded. It was entirely a private affair, as mentioned by PEOPLE. Spears shared this happy moment with sister Jamie Lynn Spears, her newborn niece Maddie Briann, dad Jamie and mom Lynne. The outdoor party brought some famous guests, including Jenny McCarthy with her son Evan, and Gwen Stefani's son Kingston, 2, who came to the bash from an equally starry affair: He celebrated Heidi Klum's son Henry's 3rd birthday at the model's Beverly Hills house along with all three of Victoria Beckham's sons.

Preston and Jayden had the best time. They drove around the party in mini motorized cars, which were customized Ed Hardy by Christian Audigier. The cars featured tattoo-inspired decals, Ed Hardy air fresheners and personalized license plates. To match up the party's theme, the cake was also in shape of a yellow truck. Wao! That's lovely. "The boys received tons of birthday gifts," a source told PEOPLE. "Britney and her family really made the party special for the boys."

Happy Birthday Boys!