Matthew Macfadyen won best supporting actor at London's Royal Festival Hall. The star overcame stiff competition in his category from the likes of Stephen Graham in Time - the Shrewsbury Prison-based drama - as well as It's A Sin's Omari Douglas and Callum Scott Howells.
The gong was for series three of the popular Sky Atlantic show, and filming has almost wrapped for series four.
Reading a congratulatory message from cast member Nicholas Braun during the acceptance speech, Armstrong said: "He said 'There's no-one I'd rather have kiss me tenderly on the forehead than Matthew Macfadyen. I kept asking for more takes and eventually, Jesse, a great man with a cool vibe, brought me into a room and said Nick, we've had enough forehead kisses so go home now'."
The series centres on the Roy family, the dysfunctional owners of Waystar RoyCo, a global media and entertainment conglomerate, who are fighting for control of the company amid uncertainty about the health of the family's patriarch, Logan Roy
The highly-anticipated fourth series could air as soon as next year and Armstrong told a group of journalists at Sunday night’s awards that the team is nearly there.
“We are just almost wrapping up the season,” said Armstrong, who is also famous for creating the hit comedy Peep Show.
“We write and we do it here in London, so the American writers come over. I always have some ideas to go into it with but they are really good people to talk about the nuances of a character and the world watching the show.”
Armstrong was tight-lipped about the plot, which will pick up after arch-patriarch Logan Roy (Brian Cox) revealed he was in cahoots with Tom Wambsgans played by Macfadyen, and his kids are reeling, and Armstrong said he still doesn’t have an overall end date for the show in mind.