Growing up in Hermonsillo , Mexico, Octavio Moreno entered a couple mariachi contests when he was in junior high and high school, and even made it to the regionals one year. But he never thought of singing as a career - he was going to be a physicist or poet.

Yet when he returned from his first day of registration at his college, had had signed up as a music major. Eventually, with the urging of one of his music teachers, he made the switch to opera from mariachi music and in 2008-10 was a Houston Grand Opera Studio Artist.

Now he's back at Houston's Wortham Theater to once again to sing the lead role in Cruzar la Cara de la Luna (To Cross the Face of the Moon), returning once again to his mariachi roots with the entire original cast after previous performances here and in Paris. Jose "Pepe" Martinez the music director of the esteemed Mariachi Vargas de Tecalitlan wrote the music and co-wrote the lyrics.

In the one and only mariachi opera, commissioned by the Houston Grand Opera for its HGOCo Song of Houston: Mexico 2010 project, baritone Moreno goes from a young man in his early 20s to the same man in the 35-45 age range and then to his character Laurentino at 70-80 years old. And back again.

As he put it, learning the very quick costume changes were a challenge at first, but now he's fairly practiced at them. Playing Laurentino at different ages enables him to tell the story of a man who left behind his family in Mexico when he moved to the United States and who at the end of his life wants to introduce his American family to his Mexican one.

Moreno says the trip to France was a success beyond their anticipation - word of mouth after the first show there meant sell outs by the end and a waiting list of people who couldn't get in. "We were like rock stars," he says.

The whole idea for a mariachi opera he says, started when the HGO studio artists were taken on a field trip to a ranch and at someone's urging, Moreno sang a mariachi song. Anthony Freud, the former CEO/general director of Houston Grand Opera (now with the Lyric Opera of Chicago) heard him and asked if there had ever been a mariachi opera.

"Two weeks later he called me to his office. He said 'OK, I think we can have a project. A year later it's on its way." Moreno says he recommended the Mariachi Vargas group as the authorities in mariachi music.

During his time back in Mexico, Moreno says he has been teaching voice lessons, performing at occasional concerts including one in China and writing most of the songs and performing on his own mariachi CD that is about to me released.

Now that he has his green card, he and his family plan to resume life in Houston. "Opera in Mexico City is big. The thing is the flow of money for art is very little. There are many opera companies in Mexico especially in the big cities. The problem is getting private donors, It's very hard to get them involved," says Moreno adding that his favorite composer to sing is Verdi.

Asked about the number of good opera singers coming out of Mexico, Moreno says: "Unfortunately we have to go outside of Mexico to have a career. Once you make it outside then it's easy to move back."

Why should people go see this? "First of all because it's something new. And in this world we should be open to new music," Moreno says. "It's filled with emotions that I've seen in the golden age of Mexican movies. It's just so realistic. It takes realism a step further. It's something that really happens. More than one family has gone through this."

Performances of Cruzar la Cara de la Luna are 7:30 p.m. March 21 and 24 and at 2 p.m. March 23 and 24 ath the Wortham Theater Center, 501 Texas Avenue. For information call 713-228-6737 or visit houstongrandopera.org. $25-$145.