The ‘Game of Thrones’ alum stars alongside Haley Lu Richardson in the Peacock spy thriller

Emilia Clarke’s latest performance in Ponies didn’t come easy.

The Game of Thrones alum stars alongside Haley Lu Richardson in the new Peacock thriller series, which follows Bea (Clarke) and Twila (Richardson), two widows of CIA agents who take their husbands’ places in Moscow as CIA operatives.

To play Bea, Clarke, 39, had to speak in Russian for what she tells PEOPLE was “a significant portion of… the experience of filming Ponies.”

“It was a lot,” she says. “It was like, 75 to 80% of my time was learning Russian.”

Clarke clarifies that she “learned the Russian lines,” but “did not learn the Russian language” as part of the role.

“That was incredibly hard,” she said at the Wednesday, Jan. 14 premiere in New York City. “That was one of the hardest things I’ve ever had to do on-camera — and I’ve done some hard stuff.”

The Russian didn’t initially deter her from taking the role, though, for one specific reason. “I didn’t acknowledge it because I’m a dumbass,” Clarke says. “I didn’t acknowledge it.”

The series, which was created by David Iserson (Mr. Robot, New Girl) and Susanna Fogel (The Flight Attendant, The Spy Who Dumped Me), premiered on Jan. 15 on Peacock, and Iverson tells PEOPLE that they lucked out getting “the cast of our dreams.”

“We really compromised on nobody and we got the best versions of everybody that we could,” Iserson says. “I mean, Emilia and Haley, I think we could have made the show with worse actors and it would have just wouldn’t be as good and nobody would have known. They’re not only great, but they just have so much chemistry together. You just love them, and it just pops immediately.”

Beyond Ponies, Clarke has also made headlines in recent weeks for her GoT reunion with Jason Momoa, who played Khal Drogo on the series, in which she gained notoriety for her performance as Daenerys Targaryen. The two crossed paths during a recent visit to The Kelly Clarkson Show.

“New York has given me so many things to be grateful for on this trip and just when I thought it couldn’t be better…look who walked into my dressing room,” Clarke captioned the post on Thursday, Jan. 15, featuring a photo of her and Momoa, 46.

Ponies is now available to stream on Peacock.