Alanis Morissette is staying 'Up All Night.'

According to TVLine, Morissette will play a former member of Ava's (Maya Rudolph) music group, Sound LLC. Talk show host Ava's musical past was previously touched upon when Lonely Island's Jorma Taccone guest starred as her ex-boyfriend.

Morissette has previously done guest spots on 'Sex and the City,' 'Weeds,' 'Curb Your Enthusiasm' and 'American Dreams.' Her episode is set to air in early 2012.

In other casting news ...