Helen Mirren
Why She’s a Good Match for Smith: Downton can be such a stuffy place, it would greatly benefit from a blast of the fresh-aired sexiness that Mirren just naturally exudes even at age 67. Having her around would tease out the randiness that you just know lurks beneath the Countess’s snappy exterior. Not to mention that she’s probably the only female guest who could ever get a rise out of the eternally proper Carson.
Who She Should Play: A suffragist and sexual libertine who takes the directionless Edith under her wing, much to the Countess’s initial chagrin… and subsequent pleasure.

Read more: Downton Abbey: Other Stars Who Should Take on the Dowager Countess