It seems that actress Rose Byrne ("Troy") is in negotiations with 20th Century Fox to join the cast of the upcoming prequel "X-Men: First Class". The Hollywood Reporter website is reporting that Byrne will be playing famed scientist Dr. Moira MacTaggert, who was previously played by Olivia Williams in "X-Men: The Last Stand". They are also stating she will be a love interest for Professor X (James McAvoy).
Now if only we knew who would be playing the younger versions of Cyclops and Jean Grey in the film...