LOS ANGELES: The Love Story hitmaker- an American singer-songwriter-asked the pop diva to make a cameo at her concert in LA, but Lopez was apparently unpleasant to deal with. “Jennifer was exteremely rude to some of Taylor’s closest friends backstage,” a source told Star magazine. “Jennifer made it clear they shouldn’t look in her direction or speak to her. “Now Jen is on Taylor’s bad list – right along with her numerous exes.  Taylor has decided she will never work with J.Lo again or even invite her to a performance. Day back, Swift and Hailee  wanted Venice restaurant to please just say yes but were denied entry!–SP