Aidan Gillen (/ˈɡɪlən/; born Aidan Murphy; 24 April 1968) is an Irish actor. He is known for his portrayal of Petyr "Littlefinger" Baelish in the HBO series Game of Thrones (2011–2017), Dr. J. Allen Hynek in The History Channel's Project Blue Book (2019–2020), Tommy Carcetti in the HBO series The Wire (2004–2008), Stuart Alan Jones in the Channel 4 series Queer as Folk (1999–2000), John Boy in the RTÉ series Love/Hate (2010–2011), Aberama Gold in the BBC One series Peaky Blinders (2017–2019), Queen's manager John Reid in Bohemian Rhapsody (2018), and CIA in The Dark Knight Rises (2012); he also hosted seasons 10–13 of Other Voices (2011–2016).
Gillen has won three Irish Film & Television Awards and has been nominated for a British Academy Television Award, a British Independent Film Award, and a Tony Award.
Gillen was born in Drumcondra, Dublin. He was educated at St. Vincent's C.B.S. in Glasnevin. He began his acting career as a teenager with the Dublin Youth Theatre, playing Nick Bottom in A Midsummer Night's Dream at the Project Arts Centre before moving to London.