Mulgrew's is an elegant beauty. Elegance, I think, is a trait that some people find very sexually appealing and others are less affected by.
Yes, elegant is another good descriptor.
I consider Kate to be 'old money', and it shows. She's got a level of refinement that qualifies into a category we rarely see now days: Actor.
Not "star" or "celebrate"... those are not the same thing as Actor.
The woman has class, and I consider that pretty damn sexy.