Brother and sister Eli & Kali both want to makeover each other's boring bedrooms. But will they be able to keep their decorating plans under wraps while they work in the same house?

It'll take some secret maneuvers to pull it off, so Diane and the gang bring in the on-screen brother & sister team Alexa Vega and Daryl Sabara — of Spy Kids fame — to help this real sibling duo complete their own mission impossible.

Eli's into spies and Kali really digs the '50s. Find out how well this brother & sister know how to create each other's dream digs in this special celebrity episode.