"Game of Thrones" actor Iain Glen will sheath his sword long enough to make a guest appearance in Season 3 of "Haven," according to EW.com.

Glen ("Downton Abbey"), who appears in Episode 6 of the Syfy series, will play a man seeking retribution after being trapped inside his home for nearly three decades.

In addition to Glen, Claudia Black ("Farscape") and Nolan North were also recently announced as guest stars for Season 3, which premieres Sept. 21.

On "Game of Thrones," Glen plays Ser Jorah Mormont, a veteran knight serving the exiled princess Daenerys Targaryen (Emilia Clarke) and her three newborn dragons.

Featuring 13 episodes, the new season of "Haven" picks up immediately following the events of Season 2's finale where Nathan (Lucas Bryant) was warned against pursuing a romantic relationship with Audrey (Rose); Duke (Eric Balfour) learned his family legacy was to kill Haven citizens with troubles; Audrey went missing, and Nathan and Duke engaged in a seemingly deadly argument.

"Haven" averaged 2.55 million total viewers during its second season, including 995,000 adults 18-49, 1.14 million adults 25-54 and a 1.9 HH rating. It rose 4 percent among total viewers and 5 percent among Adults 18-49 compared to Season 1.

Based loosely on Stephen King's novella "The Colorado Kid," "Haven" follows Audrey's investigations of a small Maine town where a substantial number of residents possess supernatural abilities. As her investigation progresses, she teams with local cop Nathan Wuornos (Bryant) and soon discovers shocking secrets about her own life.

The series is produced by Entertainment One and Big Motion Pictures in association with Shawn Piller, Lloyd Segan and showrunner Scott Shepherd ("Tru Calling," "The Dead Zone"). It airs on Showcase in Canada and internationally on Universal Networks International’s channels.