It's always difficult when kids watch their divorced parents date other people. But Jess ( Zooey Deschanel ) is about to live through her worst nightmare on New Girl when her dad ( Rob Reiner ) brings his new girlfriend Ashley over to the loft. Because his new arm candy is none other than It's Always Sunny in Philadelphia's Kaitlin Olson! Ashley went to high school with Jess and is the same age as Jess.