His acting was all smiles and scowls, and his dancing fell short of Broadway calibre, but Yang Yoseop, at 23, was an old pro at exuding heartache - which was all that really mattered.
At a recent performance in Seoul of Joseph and the Amazing Technicolor Dreamcoat, the Andrew Lloyd Webber-Tim Rice rock musical, the 1,000-strong audience fell into a mesmerised silence every time the spotlight fell on Yang, the sweet-faced K-pop star from boy band Beast.
The hush broke only once, when Yang, playing the much-abused son of the biblical Jacob, sang a Korean translation of Joseph's power ballad Close Every Door. As he belted about hardship and hope, young women wept.
"He looked like he did in Caffeine," says Jung Jeong-un, 17, during the intermission, referring to Yang's K-pop video. "Yoseop's hurt feels very deep. I love him." So much so that she had already bought another US$80 ticket to his next performance in Joseph.
Imagine Justin Bieber in a Broadway show, and the hottest trend in South Korea's US$300 million theatre market - which is crowded with US and European musicals - starts making sense.
Not unlike Broadway's star casting of movie and television actors such as Daniel Craig and Bryan Cranston, producers in Seoul have been increasingly hiring K-pop stars and Korean soap opera actors to perform two or three times a week in major roles (with other actors handling the other nights).
The stars like the prestige of the roles and get payments of US$50,000 per appearance.
The fusion of home-grown performers with US and European shows has meant big money - and lucrative royalties and fees for the show creators - by turning women in their teens, 20s and 30s into devoted and repeat customers.
In the theatre lobbies of Joseph, Grease and Bonnie & Clyde during recent months, they snapped photos of each other standing beside life-size cut-outs of K-pop stars in costume. At Ghost the Musical, a Broadway flop that has opened its first Asian production in Seoul, competing fan groups used a large pair of scales near the box office to weigh rice donations they made to charities on behalf of the musical's K-pop and soap stars.
Television and radio advertising emphasise the K-pop stars first and the show titles second for the dozens of musicals running in the city.
"Ten years ago, five years ago, ticket sales depended on a musical coming from Broadway or London or having a Tony Award. But today, K-pop casting has become the number one criteria for a lot of shows," says Chang Jun-won, a talent agent turned producer whose latest show is a Korean version of Murder Ballad.
"The stars bring in women, but they're also famous enough to bring in Japanese and Chinese tourists, whom we need badly to keep growing our market," he says. A few Korean theatre producers are riding this wave by putting K-pop stars into Broadway musicals and taking the shows to Japan. A K-pop Jack the Ripper was a popular export to Tokyo last year.
The goal is to take these tours to mainland China, once its enormous market opens up further to outside theatrical productions. But most theatre activity is centred in Seoul.
Producers focus on rotating big-name singers into musicals to help them have longer runs. And when those performers are on tour, soap stars and others will suffice, such as Lee Ha-ni, a onetime Miss Korea, playing Sarah Brown in Guys and Dolls.
"There are so many musicals in Seoul now, dozens and dozens, that the stars help ticket buyers make choices," says Gina Lee, the director of Guys and Dolls, who cast a former K-pop singer, Song Won-geun, as the gambler Sky Masterson.
Mastering the English-to-Korean translation is one of the challenges facing the K-pop stars, several of whom said that they dreamed as children about acting on the stage, but were pulled into the K-pop world because the talent agencies and music-making assembly lines have become so dominant here.
Ock Joo-hyun, who plays Elphaba in Wicked, says that the make-believe world of theatre - like adjusting to green make-up at every performance to play her character, who becomes Wicked Witch of the West, was unnerving.
"I had never been raised in the air before, and I got a little motion sickness the first time on the broom," says Ock, who then smiled and winked - a K-pop move that seemed almost involuntary to her.
Yang, whose slightly androgynous features were pronounced "cute" and "sweet" by several girls during and after Joseph, says he is trying the theatre for the same reason some Hollywood stars go to Broadway: to prove something to his fans and to himself.
"Popularity can just be a bubble when there is no ability," he says. "So I'm coming to the theatre to learn abilities. K-pop gives you fans, but I hope that musicals can give you skill."
The New York Times