It’s Always Sunny in Philadelphia‘s Kaitlin Olson is about to cause a perfect storm on New Girl.

The actress is set to recur in Season 4 of the Fox comedy as Ashley, Jess and Cece’s onetime high school nemesis who is now engaged to Jess’ father Bob (returning guest star Rob Reiner), TVLine has learned.

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Olson, who joins previously announced Season 4 Newbies Jessica Biel and Reid Scott, will debut in Episode 3, which is slated to air in late September.

New Girl‘s fourth season kicks off Tuesday, Sept. 16 at 9/8c.