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It was clear from their reunion earlier this season that Ava (Maya Rudolph) and Walter (Sean Hayes) share a flair for the dramatic, so you just know that the two will pull out all the stops for Halloween!

But that requires a lot of practice, as you can see in ETonline's exclusive sneak peek from Thursday's all-new Up All Night!

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Watch Ava and Walter find their ghoulish groove and tune in to Up All Night Thursday at 8:30 p.m. on NBC.