‘Les Miserables’ star Eddie Redmayne on his ‘X Factor’-style audition and being dragged through freezing sewers by Hugh Jackman

As the romantic revolutionary Marius, who woos Cosette (Amanda Seyfried) and enthralls Eponine (Samantha Barks), Tony Award winner Eddie Redmayne stands out in an outstanding, SAG-nominated ensemble cast. The freckle-faced "My Week with Marilyn" star, 31, sings sweetly and cries heartbreakingly as a young man who falls in love at first sight. The British-born actor is the movie's breakout male star, a fact that wasn't lost on his co-star Barks: "I think the world of Eddie. He's such an approachable, lovely man, and getting to die in his arms was an absolute joy. I didn't know he sang, and all of a sudden this angelic voice comes out. His control over his falsetto and upper vocal range floored me."

Thelma Adams: When did you first see "Les Miserables"?

Eddie Redmayne: I'd seen the thing when I was 7. I wanted to be Gavroche, the little rock star guy, since I was young. Even on set I was living vicariously through Daniel Huttlestone, who plays Gavroche onscreen. I still want to be that kid. The idea of building dens and barricades is every 10-year-old's dream.

TA: What were you first, an actor or singer?

ER: I sang first when I was a kid, and I got into acting when I was 11 or 12. I did play urchin No. 30 in Cameron Mackintosh's "Oliver," directed by Sam Mendes. I never met Sam because I was so far at the back.

TA: How did you nail this role? Did you have to audition?

ER: I was filming "Hick" with Chloe Moretz and Alec Baldwin in L.A. in a field in the middle of nowhere. Suddenly I had two hours off, so I went to my trailer and filmed myself singing Marius's song on my iPhone. I sent it to my agents to show I was interested. I had worked with Tom (Hooper) for the TV miniseries "Elizabeth I," and Nina (Gold) had cast me in "My Week with Marilyn." But they were friends – and they didn't know about my singing.

TA: How hard was the audition process after that?

ER: Rigorous. It was an "X Factor"-style audition in front of the lyricist, the composer, Mackintosh, the producers, the director, and Nina. I have a newfound respect for American singers on "The X Factor." The pressure mounted. But knowing that so many people in the world loved this story weirdly made it easier because I kept pushing myself until I reached the emotional core of it.

TA: You see actors gaining weight or losing weight for a role. But it seems like you must have had to muscle up your vocal cords for this role.

ER: Mark Maitland was my vocal coach. Training your tongue and throat muscle was like training for a marathon. We had to be able to sing take after take after take.

TA: There's been a lot of fuss about the use of live singing on "Les Mis," as opposed to lip-syncing to a prerecorded tape. What was that like?

ER: It was a constant debate between serving the musical and prioritizing the storytelling. Tom (Hooper, the director) described it as thinking in the present tense -- not songs, but spontaneous. The challenge was finding that freshness but still serving this beloved score.

TA: And then there's the singing and crying -- how do you sustain the emotion when there's so much buzzing around you on set?

ER: Amanda Seyfried said that sets are rhythmically weird places. You work hard for an hour and then take a two-hour lunch break. The challenge is keeping your place emotionally. A lot of actors take themselves off to their music or iPhones. What was wonderful here was having the music actually playing in your ear to sustain that emotional pitch on camera.

TA: When I interviewed Anne Hathaway, who plays Fantine, she said: "We bonded by the fact that even though Russell and Hugh (Jackman) had so much experience, we were all doing something for the first time, the live singing. Because of that, we were all really open to each other and supportive and invested. If Eddie had a breakthrough with something, he shared it with us."

ER: It felt like a serious collaboration with Hugh, Russell, Annie, Amanda, and Sam. Everyone was so supportive because no one knew exactly what we were doing. The new process was a great leveler. We were all out of our comfort zone.

TA: Hathaway also said that Hugh set the bar high, as a leader, both offscreen and on.

ER: When the first person on the call sheet was such a leader and a team player, it meant that the whole thing had a wonderful feel to it. Jean Valjean, the character Hugh plays, is a virtuoso part. It demands vocal range, emotional range, and you've got to be uniquely strong physically. Tom says "Les Mis" would not have happened if not for Hugh. Consider his grace, his nobility as a person and as an actor, through an incredibly grueling shoot. And then there were the physical demands in freezing water while singing with hundreds of extras, let alone him losing the weight and then regaining it. I've never seen a commitment like it.

TA: What was the hardest part for you physically?

ER: Being pulled through the sewers by Hugh, although it was harder for him. It was crappy and freezing cold, and the moment when Sacha Baron Cohen comes and steals a ring and we were playing dead, and I couldn't hold still -- "I'm sorry," I said, "I can't stop shivering."

TA: What was your most challenging day?

ER: You'd hear buzz about how staggering Annie was with her solo, "I Dreamed a Dream." I kept waiting for them to shoot my solo, "Empty Chairs at Empty Tables." My fear was getting beyond control. Then that day finally arrived. The feeling onstage in live theater is that if you have a bad night, you can sort it the next day. But I didn't want to be in the car going home at the end of the day feeling that I hadn't been my best and that it would haunt me and fans in the future. Stakes-wise, that was the most hard-core day.

Eddie Redmayne and the rest of the cast of 'Les Miserables' talk to Yahoo! Movies:

Insider Access: 'Les Miserables'