Diggs will play Layton Well, a prisoner barely surviving the harsh conditions in the tail end of the train.
Though many in her VIP position are dismissive of the lower class passengers, Melanie is curiously fascinated by them.
The TNT Snowpiercer series is a co-production of Tomorrow Studios and Turner’s Studio T, along with CJ Entertainment.
Connelly will play Melanie Cavill, a First Class passenger who works as the Voice of the Train – responsible for making the daily announcements over its PA system.