Now,thanks to a preview clip fromPeople, we have our answer.
You cant walk into that office without being boobytrapped in some way, Atwell tells EW.
Then the script came, and its an absolute incredible spectacle.

Credit: Byron Cohen/ABC
Theres some fantastic professional dancers that are in it too.
It was one of the best days of my working life, says Atwell.
Everyone was in such a good mood, everyone turned up to watch the filming of it.
Jarvis was having an absolute ball, leaving going, Im going to take up up dancing lessons now!
[And I come] away going: Oh, I think Ive got a career in singing!
Im the next Adele!
An overblown sense of our skills and talent.
But it was hysterical.
Its just something different from your every day working schedule.
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