The much anticipated Bobby Fischer chess biopic Pawn Sacrifice has added a new cast member. Robin Weigert has recently signed on to play Fischer’s mother Regina.

She will appear alongside Lily Rabe as Joan Fischer (Bobby’s sister), Liev Schreiber as Russian chess master Boris Spassky, Peter Sarsgaard as a priest and close friend of Fischer, and Tobey Maguire, who stars as the chess prodigy himself.

Weigert was an Emmy nominee for her role as Calamity Jane in HBO’s Deadwood. She currently plays Ally Lowen, the motorcycle gang’s lawyer on the hit FX series Sons of Anarchy. She also starred in the indie pic Concussion, which premiered at Sundance earlier this year and is currently in a limited theatrical release.

Pawn Sacrifice will be produced by Gail Katz Productions as well as Maguire’s Material Pictures. It’s being directed by Edward Zwick (Blood Diamond, The Last Samurai).

Filming for the picture has already begun and will take place in Montreal, Reykjavik, Iceland, and Los Angeles.