Matthew Vaughn's "X-Men: First Class" is only a few weeks away from shooting, but there are a number of key roles that still need to be cast.  So far, the prequel has recruited an impressive list of actors including James McAvoy (Charles Xavier), Michael Fassbender (Magneto), Kevin Bacon (possibly Mister Sinister), Jennifer Lawrence (Mystique), Nicolas Hoult (Hank "Beast" McCoy) and Alice Eve (Emma Frost, aka The White Queen).  Now, according to The Hollywood Reporter, Rose Byrne is in negotiations to join the group as mutant scientist Moria MacTaggert, a longtime character from the "X-Men" comic book series.

First appearing in Uncanny X-Men #96 way back in 1975, MacTaggert is a former flame of Xavier's who lead a Mutant Research Center on the fictional Muir Island off the coast of Scotland.  A supporter of mutant rights, she has a long history with many of the "X-Men" characters including Jean Grey, Magneto and Banshee.  How she will fit into the cinematic "X-Men: FIrst Class" remains to be seen.

Byrne is best known for her Emmy and Golden Globe nominated role in the series "Damages" (she recently received her second Emmy nod for the series), but has also appeared alongside Russell Brand in "Get Him to the Greek," "28 Days Later" and "Troy."  She's currently shooting the comedy "Bridesmaids" for Universal.