On the day of their wedding, Brad Oscar and Diego Prieto shared a spotlight at Arena Stage, just as they’d done almost seven years before.

Prieto was 30 in the fall of 2005 and had come out as a gay man to friends and family just the year before. Oscar was a decade older, a veteran Broadway actor still nursing the wounds of a breakup.

Both were cast by director Molly Smith in a production of “Damn Yankees.” Prieto would play the catcher, envisioned as a Cuban tough guy with a cigar perpetually in hand. Oscar, a native Washingtonian who received a 2001 Tony nomination for his performance as Franz Leibkind in “The Producers,” was cast as Mr. Applegate, the devil.

Unaware of Oscar’s credentials, Prieto didn’t know enough to be intimidated as rehearsals began that November. “Brad Oscar? Who’s that?” he remembers saying to a friend. “I didn't really know who he was, which I was grateful for.”

Oscar’s talent and pedigree soon became apparent, but Diego was more impressed by his warmth. “He was such a gracious person, really open to everybody,” he says. “And he’s hysterical. So in those interactions, you’d laugh your face off.”

Prieto had recently begun hoping the universe would send love into his life, but he never really considered Oscar, the star of the show. Before the show opened, they sat next to each other during rehearsal and Oscar playfully touched Prieto’s knee.

“That was the first time I remember there being a spark,” Oscar says. “Where I was like, ‘Oh, wait a minute.’ ”

A week later, at the opening night cast party, they kissed by the refreshment stand. These things happen — for the six-week or three-month duration of a production, actors work and play together, developing an instant but often fleeting intimacy. Prieto and Oscar promised each other they wouldn’t expect much of their “showmance.” “We were really honest about, ‘Let’s just enjoy the ride,’ ” Prieto says.

So he was surprised, two months later on closing night, to find himself suddenly overcome. “I thought, ‘Oh, my God, this is the end. I lost it — I was hysterical,” he says. Oscar asked what was wrong. “I know you told me not to, but I think I fell in love with you,” Prieto said.

Oscar also began to cry and confessed he was feeling the same way. “Initially, I just felt very easy with him,” he recalls. “But also I could see that he was very kind and just a good person. And he has this laugh that I just loved.”

They decided to see what would happen when Oscar returned to his home in New York. Prieto began making frequent visits, and with each one, Oscar says, “it got better and better.”

That September, they were both cast in another Arena Stage production. They worked and lived together throughout the entire run of “Cabaret,” “and it was great,”Oscar says. “It was just so good and easy. For the first couple years I was just sort of waiting for the other shoe to drop. But I guess if you found someone you truly connect to, it transcends a lot of the stuff that gets in the way.”

In 2007, Oscar spent eight months in Las Vegas with “The Producers.” When Prieto came out to visit, he asked if he would considering moving with him back to New York when the run was done.

Prieto was nervous about giving up life in Washington, but he’d also dreamed of someday moving to New York. Before they moved in together, the pair got matching rings as a sign of commitment. When Prieto arrived, he felt immediately at home in Oscar’s world. “Just getting to know him through his friends and his family and seeing how much people love him. And I already feel the love they’re giving me,” Prieto says. “I was just swept away. Being loved by him is not a bad place to be.”

Prieto was eager to accompany Oscar to his theater events and to go on auditions of his own. He was soon hired by a group that performs live, interactive theater for children in hospitals. Both men say there is never a sense of competition or jealousy, despite being in the same industry. “I tell him his successes are my successes, and this is something we talked through in the beginning.”

In 2009, Oscar, now 47, surprised Prieto on his birthday with a limo ride to the city clerk’s office, where they filed to become domestic partners. They started to think about a wedding once same-sex marriage was legalized in Washington, and they heard about the construction of Arena Stage’s new building, which would double as an event space.

“Whenever I thought ‘wedding’ I automatically thought how great it would be to have it there,” says Prieto, 36. Once Arena gave the nod last summer, planning began in earnest.

On April 16 — a Monday, when the theater was empty — 160 of their friends and relatives took their seats in the Kogod Cradle. A guitarist and keyboard player entertained the crowed until the wedding party arrived on stage. When Oscar and Prieto emerged from behind the center curtain, the musicians played “Here Comes the Bride” — and then quickly cut to “Take Me Out to the Ball Game.”

“Play ball!” Oscar yelled as they reached their mark, where Arena Stage artistic director Molly Smith stood waiting to perform the ceremony.

“Loving you and being loved by you is the most fulfilling gift,” Prieto told Oscar.

“You are my divine accident,” Oscar said in return.

As they walked off stage a married couple, the crowd offered the pair a standing ovation.

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