The surprises on ABC’s Shifting Gears just keep coming with Tim Allen set to reunite with his Last Man Standing costar — and onscreen wife — Nancy Travis. Us Weekly can exclusively reveal that Travis, 63, has been cast in a guest role on an upcoming episode of the hit ABC sitcom. The actress plays

But the reality is often subtler than that—career-wise, each superstar needed something from the other. Often, one act is a bit thirstier than the other. When you encounter one of these mega-duets, you should ask yourself, Who needed this more?