Cameron Diaz has been happily dating Justin Timberlake for nearly four years but is terrified of settling down and starting a family. The 34-year-old insists she has a hard time committing to specific film roles and lacks the discipline it would take to raise children. She explains, "I think everybody wants at some point to have that responsibility and involvement. But not at the moment." When asked if she was worried about the commitment she said, "Yeah, exactly, the commitment! I don't even want a dog. I don't. My cat just died, and I don't want a cat." Diaz claims it's even hard to pin her down for a specific film role, adding, "I hate committing myself to anything. "So I'm really bad at saying, 'Yeah, I'm gonna be there in three months... (It's) probably the lack of discipline, honestly. I'm a spoiled brat worried about getting my way every time!"