Playing Petyr Baelish is Tommy Carcetti from the Wire (I don't know the actor's name, but I think it might have been one of those British-type names like Aiden or Ian). Which has some parallels. Carcetti was first introduced as a guy who was shut out the highest reaches of power due to his birth (white man in Baltimore) and derives amusement from goading those in power, and who seems to get off on being in the know & having insider information. Later, during his surprising rise to power, he seems to a friend of the straight-arrow heroes, but in the end proves a bigger part of the problem than the solution, despite manipulating the system to achieve great power. Also interesting in light of Varys' assessment of the man - "Littlefinger loves only Littlefinger" - is an early scene featuring Carcetti where he has an extramarital liaison, and seems more interested in watching himself in the mirror than his paramour.

Also, I think (though I've been wrong on this subject before) that Lord Mormont is being played by Fr. Ashby from the last season of Sons of Anarchy (others may know that actor as the Irish mob boss from an episode of 'Castle' ). Both his characters we know as respected leaders of their groups who dress in black, swear vows of celibacy, and whose sisters are more involved in the main characters' problems. Both characters are having trouble adjusting to their once idealistic cause being more and more influenced by the criminal element drawn in by necessity, and both make well-meaning but ultimately tragic & misguided decisions about the disposition of male babies.

Parallels aside, it's good to start seeing familiar faces. Until now, I was only familiar with Ned & Cersei's prior work.