I'd like to point out that Julia not liking Ivy really may have something to do with the fact that Tom has a great relationship her. The whole "Ivy's his girlfriend, Julia's his wife" thing makes a lot of sense considering that otherwise, she should totally 100% back her best friend's choice for the role (someone who she knows could knock it out of the park), but she doesn't. And then she has the nerve to get mad when Tom agrees to Michael during the previews, despite him being their only option, the situation being awkward because Julia made it awkward, and Julia not backing up Tom's decisions but expecting him to blindly follow her.