It's not like he's trying to — or that he even needs to — but his work on stage in the Broadway revival of "Lend Me a Tenor," a slam-bang farce by Ken Ludwig, is so physical he's already lost about 10 pounds.
Bartha plays Max, a nervous assistant to an opera impresario in 1930s Cleveland. They've scored a "good get" by snagging a world famous tenor, Tito Merelli, for a performance of "Otello."
Max's main task is to get Merelli to the opening on time, but the plan goes awry when the singer accidentally takes too many sleeping pills. Rather than canceling the show, Max ends up disguising himself as Merelli — dressed as Otello — to pull off the performance.
The role is intense. The 31-year-old actor must maintain high energy throughout the show: running in and out of rooms, jumping on a bed, falling on the floor, singing opera and pulling off an impossibly quick costume change. Bartha likens it to feeling like a car in a car wash.
Because of those challenges, Bartha acknowledges having his breaking points.
"I've run into Victor Garber, who originated the role (of Max) in the 1989 Broadway production, and he's even said, 'Have you broken down yet?' Which does help," Bartha said. "If Victor Garber says you might break down a few times, then you know that — because you have — it might not be that bad."
When Bartha first read the script, he was drawn to the idea of playing almost three characters in one performance. There's Max in the beginning, Max as Otello and an improved, more confident Max at the end.
But Bartha soon realized the role was harder than he first anticipated.
"(Farce) is deceptively difficult," said the actor, who has appeared on film in "The Hangover" and the "National Treasure" movies. "I don't think I realized how difficult it was until halfway through rehearsals."
He also knew immediately that he wanted to work with its director, Stanley Tucci, and co-stars Anthony LaPaglia and Tony Shalhoub who were already attached to the project.
"I pictured them right away in the parts and I could not stop laughing," Bartha explained. "The actors were pushing the material along. That's kind of why I wanted to do it so badly."
Bartha says it's equally as great to be directed by a great actor.
"(Tucci) just gets it. He knows what all the actors are going through. He probably could play every part in this play better than anyone else and I think the biggest surprise is how we got right into it."
They didn't spend time exploring the story or their characters but instead focused on the technical aspect of their role and getting the timing just right.
"We would spend an hour on what sound to make when you fall on the ground or where exactly to place something," he said.
The admiration is mutual.
"Justin Bartha is one of the most talented actors I've met in many years," Tucci said. "And having never done a play before, (he) has risen to the occasion ... and then some. He should be very proud and audiences are very lucky to be able to see him making his Broadway debut."
When the show is over, Bartha says he feels both amped up and exhausted.
"Your body is exhausted but your mind is buzzing. It's bizarre. I literally sweat for pretty much the entire time and afterward you'd think you'd collapse, but you need a drink."
