"Rome" star Ray Stevenson is joining Season 7 of Showtime's "Dexter," according to EW.com.

Stevenson, who has appeared in the films "The Three Musketeers," "Thor" and "Punisher: War Zone," will play the leader of an organized Russian crime syndicate.

In November, the network renewed the series and signed actor Michael C. Hall for a seventh and eight season, each featuring 12 episodes.

"Dexter" set new rating highs last season -- counting multiple airings, DVR and on-demand viewing -- and pulled in 5.1 million viewers each week.

The series follows a serial killer (Hall) who holds a job as a Miami police forensics specialist while quenching his thirst for the kill by hunting criminals who he believes have escaped justice.

Hall was nominated for four Emmys and won a 2010 Golden Globe for his performance.

In addition to "Dexter," Stevenson is also set for appearances in "G.I. Joe: Retaliation" and the "Thor" sequel.

"Dexter" also stars C.S. Lee, James Remar, Desmond Harrington, Lauren Vélez, David Zayas, James Remar.