After a long court hearing for her custody battle on Friday, Britney Spears hit the town with her longtime friend Alli Sims ? and Dallas Cowboys' quarterback Tony Romo. The pop star, dressed in a masquerade ball mask, and Sims first made a quick stop at the L.A. restaurant Ketchup where Romo was having dinner. "[Spears] walked around the restaurant into the lounge where she met up with some people," an observer tells PEOPLE. "She didn't eat or drink ...[It] seemed like she was rounding up people to go [out]. She was very friendly and smiley, in and out." Another source says, "Alli was meeting up with Tony and his friends at Ketchup, and Britney wanted to come along. Tony and Alli have been good friends. They've known each other for a little over a year. "