Britney Spears is no stranger to odd antics, but her behavior on January 7 was particularly bizarre. The “scantily clad” pop star showed up at a Beverly Hills elementary school, saying she was there to pick up someone else’s kids. (She lost custody of her own sons January 4 after being rushed to the hospital. She blew off a custody hearing yesterday.) The singer parked her car outside the school just before 3 p.m. and spent 10 minutes smoking cigarettes and talking to herself while she waited for classes to let out. “She was just rambling and confused,” says the witness, who approached Spears to ask if she was OK. “She said, ‘I’m here to pick up my kids.’ But then she changed her story and said, ‘They aren’t my kids; I have a new attorney, and I came to pick them up for her.’” Adds the witness, “All I could think was, Who in their right mind would let her pick up their kids?” As children began to leave for the day, the star, 26, caused a commotion — “It became the talk of the school. Some of the kids were freaked out,” says a school source. She was directed to a more secure entrance around back. But before getting into her car and driving off (without any children), she chatted up the female witness: “She said, ‘You’re so nice. You should give me your number. I don’t have very many friends.’"