Before my opinions on her get misunderstood, let me be clear. I appreciate her talent and physical beauty in equal measure. She's going to bring the depth regardless of how they present her.

They wouldn't have hired her otherwise. As rebo said, they don't need an A-lister in a small role. They need her talent for something that character provides within the story. We'll have to wait and see.

To put it more clearly with regard to how I feel about her physical beauty; why CGI over her at all? Why can't she bring gravitas to the character (which is a given), as well as be seen? Why an alien? Why not a human as a close friend or pivotal character?

To borrow from an episode of Doctor Who where a character sits on a planet-destroying weapon, much to the dismay of the person wielding it;

War Doctor: Don't sit on that!
Moment: Why not?
War Doctor: Because it's not a chair, it's the most dangerous weapon in the universe.
Moment: Why can't it be both?