Star magazine has learned that, before their Hawaiian getaway, Cameron Diaz dissed her younger boyfriend Justin Timberlake of *NSYNC for being a “Mama’s boy” because Justin wouldn’t buy a Malibu love nest for the couple without his mom Lynne Harless’s approval. “Although Cameron and Lynne get on really well, Cameron felt enough was enough,” a source revealed. “She attacked him for needing his mom’s approval to move in with her. This really upset Justin, and they got into a big shouting match in front of the realtor showing them around the Malibu property.” Cameron was also mortified when Justin’s mom showed up at a New York City club at the end of August. Justin has since promised Cameron he would talk to his mom. “They’ve got things worked out now and things are back on track,” the source added.