'Broadchurch' Actor Matthew Gravelle on the Secrecy Surrounding Season 2 and Joe's Not Guilty Plea

When Joe Miller (Matthew Gravelle) confessed to murdering 11-year-old Danny Latimer in Broadchurch's Season 1 finale, no one expected to see him return in Season 2. Gravelle certainly didn't once he was informed Joe was the killer with a few weeks left in shooting. “I'd written myself out of the equation,” he says. So when it came time to film the second season of the drama, which premieres March 4 on BBC America and finds Joe entering the shocking plea of not guilty, producers wanted to keep his involvement a secret.

Step 1: They had Gravelle stay in a separate hotel from the rest of the cast for the four-month shoot and limited socializing. “Just in case the public saw us all together and put two and two together and leaked anything,” Gravelle explains. “As much as I desperately wanted company, I didn’t get any.”

Step 2: They asked him to wear a disguise to and from set: “I wasn’t in during that first week [of filming], and the costume designer called me and said, ‘Matthew, could you bring some hats with you? And a couple of coats?’ So I was kind of like, ‘What’s this? Why?’ And he said, ‘Well, because we’ve got a lot of photographers, and we’re gonna have to try to cover you up the best we can to try to keep this secret.’ So I took my hats, and they very kindly laid out a selection of wigs for me to choose from. I chose the least offensive, which was still pretty offensive — a kind of rank, straight, blond, greasy-looking nylon wig that was very itchy as well. I think I rocked it, in my opinion, but I’m not sure everyone would agree,” he says. “I also wore dark glasses and a hoodie, as if to try to cover up the fact that I was wearing a suit,” he adds. “I felt like an idiot.”

Related: 'Broadchurch' Season 2 Primer: Who's Who

Producers played that game of solitary when filming Joe’s entrance in the Season 2 premiere as well (watch it below). To capture the raw emotion of seeing child-killer Joe again for the first time, they kept Gravelle hidden from the other actors until he walked into the courtroom. “We had the table read, and then from that point on, we didn’t see each other until I walked out for that scene,” he says. “We didn’t even rehearse it. We’d been kept apart from each other for the whole of that day, so it was really intense. You could feel it when you walked into the dock. I had all these hateful eyes looking at me.” (That was not the reaction he got from fans after Season 1, by the way. “I had people going out of their way to come up to me and say, ‘You were in Broadchurch! I loved that. It was fantastic!’ rather than vile or hatred,” he reports with a laugh.)

On one hand, spending the season sitting in the dock listening to people testify was fun: “No dialogue is easy, because there’s nothing to learn,” he jokes. “You just listen and react to what people are saying about you. It was a new challenge. And I got to read a lot of books as well, which is great.” (He recommends Patricia Highsmith’s Deep Water.) On the other though, he found himself feeling increasingly withdrawn. “When we started shooting the courtroom scenes, and I’d been kept away for that amount of time, I’d come into work in the morning and really want to speak to everybody and within about five minutes of being shut away in my glass box, I felt like I wanted to keep away from everyone. I lost all of my social skills during that shoot,” he says.

Related: 'Broadchurch' Review: New Mysteries About Old Secrets

Once again, he only found out Joe’s fate a few weeks before filming wrapped. Our exclusive clip below reveals that even Rev. Paul Coates (Arthur Darvill), who’s been visiting Joe in jail, had no idea he’d plead not guilty.

"It was like a trapped rat reaction, and ‘not guilty’ popped out," Gravelle says. "The options for him are, I spend the rest of my life in jail as a child-murderer and I die in jail, or I have a go and see if I can somehow get off or reduce the sentence."

Joe’s line, “Nobody’s innocent, Paul. Everyone’s hiding things,” hints at another motive. Does he want to see those who’d condemn him judged? “He’s just not very good at admitting his own guilt and his own fault in this. He feels he’s a victim of circumstance, which from the audience’s point-of-view is clearly ludicrous,” Gravelle says. “But he definitely believes that had he not been pushed into that situation by Dan, he certainly wouldn’t have reacted like that, and it was probably the community that made him want to seek solace in this relationship with this boy. He’s a bit of a coward, really.”

Season 2 of Broadchurch premieres Wednesday, March 4 at 10 p.m. on BBC America.