By Ruth Kinane
May 29, 2020 at 08:30 AM EDT
Left Bank Pictures

In September 2001, Charles Ingram found himself in the hottest seat in the U.K., under the bright lights on Britain's buzzy game show Who Wants to Be a Millionaire? But after the confetti dropped and the £1 million check was presented to Ingram, the show's producers grew suspicious — deciding that he, along with his quiz-crazy wife, Diana, had conspired with a coughing audience member to cheat their way to the top prize.

Based on the true story and adapted from the stage play of the same name by James Graham, Quiz (premiering May 31 on AMC) brings the action back to the small screen where it all began. We chatted with stars Matthew Macfadyen (Succession) and Sian Clifford (Fleabag) to get their final answers about working on the miniseries.

ENTERTAINMENT WEEKLY: What was your initial reaction to this project? Did you guys watch the show back then and remember the scandal?

SIAN CLIFFORD: I was immediately gripped. I remembered this story so well; you couldn't escape it if you were living in this country. The press attention that it got was insane. I looked Diana up, and I was like, "Wow, I think I could pass for her."

MATTHEW MACFADYEN: I was on a yacht in Croatia with all the Succession people when the script came through. It was just such a brilliant bit of writing. I remembered it happening years ago, but not vividly. I think everybody watched Who Wants to Be a Millionaire? back then. It was such a phenomenon. It really was event TV.

How did you go about researching these real and still living people?

MACFADYEN: I watched a little footage, but it's all there in the script, really. I knew I wasn't trying to do an impersonation; it wasn't rigorous carbon copy. Our brilliant makeup designer, Julie Kendrick, produced the false teeth, and they really helped. It was like putting on a sort of magic cape: I felt completely different. Then, before we filmed the scenes in the chair, Michael [Sheen, as Millionaire host Chris Tarrant] and I would look at segments from the real show together and then go for a take. You take little bits and pieces, just to get the flavor of it.

CLIFFORD: I watched Charles' episode, but the version on YouTube is edited with the volume of the cough turned up, so I watched that more for physical traits. I stayed clear of any newspaper reporting because I found it so biased. She was not in their favor at all, portrayed as this Lady Macbeth figure, and I just knew intuitively that wasn't who she was. Basically, I wanted to get to the heart of her as a human being.

Mark Johnson/Left Bank Pictures

Did you meet the Ingrams?

MACFADYEN: They came to set on our last day of filming. They were lovely, really sweet.

CLIFFORD: Yes, them coming on the last day was a conscious choice, on all our parts, to protect them and the integrity of the show. We didn't want to be too influenced by meeting them, and we wanted to do James' script service. He'd spent so much time with them, I just knew inherently that he captured them. When I met her, what was remarkable was this radiant sweetness that I'd picked up on — that's very subtle on camera — is just so present. So, I'm glad I stayed true to that. I really hope that I've done her justice.

Michael Sheen is so convincing as British TV icon Chris Tarrant. Did you ever forget it wasn't really Tarrant?

MACFADYEN: He's very clever, Michael. Our first scene was in the courtroom, where Tarrant gets up and gives evidence. Everyone just spontaneously laughed, because Michael had the voice just perfect and the shoulder pads in his suit…

CLIFFORD It's a total transformation, and it took hours. The sweat that would pour off Michael's head under those lights… I don't think it was the most comfortable experience for him, but it really helped with the whole immersive experience. Matthew would say that when you were opposite Michael, you'd forget what the real Chris Tarrant looked like.

Matt Frost/Left Bank Pictures

They also built a replica Millionaire studio. Was it intimidating sitting there even just pretending to play?

CLIFFORD: Yeah, we really relived the tension of those moments. That music is designed to get under your skin, and it works. It's very, very easy to get sucked in.

MACFADYEN: There was no imagination required. The sound cues and lighting cues were brilliant. Truthfully, my heart was banging away.

There are also many funny moments. How did you amplify the inherent comedy of the situation without mocking anyone?

CLIFFORD: My favorite stories are human stories that don't have an agenda. That's why I love Phoebe Waller-Bridge's writing. It's why I love Succession. It's why I love this show. It's human, so of course it's funny. Of course it's tense. Of course it's awkward.

MACFADYEN: You have an ear for what's funny, but ultimately you play everything straight down the line and truthfully. If the scenes are written in the right way, the humor comes out. In fact, the more seriously you play it, the funnier it is. I came away more thoughtful about people's rush to condemn and I think — certainly in these times we live in now — that's something we should keep in check a little.

The first episode of Quiz airs Sunday, May 31, at 10 p.m. ET on AMC, with the second and third episodes following June 7 and 14.

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