Weiner wrote and will direct the pic, which Gilbert Films is producing, with Lionsgate handling international sales.
Gary Gilbert, Scott Hornbacher and Jordan Horowitz will produce. Lensing is set to begin in May in North Carolina.
Wilson and Galifianakis will play childhood best friends who go on a road trip after Galifianakis’ character inherits significant coin following the death of his estranged father. Poehler would play Galifianakis’ sister.
“This movie has been my passion for eight years, and to see it come together with Owen and Zach and Amy is a dream come true,” said Weiner. “I can’t wait to get started because the movie is about everything I care about, and I’m tired of reading it out loud to my friends.”
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“We are thrilled to finally bring this project to the screen,” said Gilbert. “Matt is one of the brightest creative minds in television, and we are confident that this project will solidify the same reputation for him in the world of narrative film.”
Weiner, who has lensed numerous segs of his Emmy-winning AMC drama series, previously directed the little-seen indie pic “What Do You Do All Day?,” a comic autobiography that debuted in 1996 at the Santa Barbara Film Festival.
Gilbert and Horowitz were producers on “The Kids Are Alright,” while Gilbert’s past credits also include Kenneth Lonergan’s “Margaret.” Gilbert Films recently produced the Lizzy Caplan pic “Save the Date,” which debuted at Sundance and is still seeking distribution.
CAA reps Weiner and Galifianakis, who is also repped by Brillstein Entertainment Partners. UTA reps Wilson, while WME and 3 Arts Entertainment rep Poehler.