Cameron Diaz and Ashton Kutcher hammed it up with lots of smiles and laughs stopping by TRL yesterday afternoon. After a long day of TV appearances, neither half of this What Happens in Vegas  duo made it out to last night's big huge A-List event, the Costume Institute Gala . Ashton and his fashionable wife were surprisingly not on the expected attendee list, but Cameron was set to be dressed by Dior for the night . Considering her emotional month, can't blame Cam for wanting to skip out on a red carpet or two but after last year's stunning look  we were looking forward to seeing what she pulled out this year. Hey, we'll take what we can get and seeing her smiles back again are more than good enough.