Natasha Leggero and Estelle Harris

Seinfeld's Estelle Harris and comedian Natasha Leggero have landed multi-episode arcs on NBC's new comedy Are You There, Chelsea?, TVGuide.com has learned exclusively.

Based on Chelsea Handler's best-selling book, the series revolves around a youthful, opinionated and sexually aggressive Chelsea (Laura Prepon) who works at a bar and drinks away all its profits.

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Leggero, who frequently appears on the Chelsea Lately roundtable, will portray Nikki Natoli, the ex-girlfriend of Rick (Jake McDorman) who gets a job at the sports bar. Nikki has a difficult time relating to Chelsea and other people who, in her mind, are not as classy as she is. In turn, Chelsea will take a liking to Nikki's loud and often offensive grandmother Tess (Harris), who pushes Nikki's buttons.

Harris and Leggero, who recently starred in NBC's short-lived comedy Free Agents, will appear early on in the series, which will premiere Wednesday, Jan. 11 at 8:30/7:30c on NBC.