Hmmm.
I'm gonna guess Karen Gillam. Nebula from Guardians of the Galaxy and Amy Pond from Dr Who a few years back. That's good nerd cred.
Unless their connections to Jim Cameron got them Sigourney Weaver... that'd probably be the ultimate nerd cred.
Oh God... it's not Kaley Cuoco, just cause she's on Big Bang Theory? Or maybe Miyam Bialik from the show, who's at least a real scientist.
Nahhh, my guess is Karen Gillam.