Salsa superstars Rubén Blades and Gilberto Santa Rosa crossed paths over the years – Blades sang last year on Santa Rosa‘s Grammy-nominated album “Irrepetible” – but they never shared a microphone on stage until the Chicago White Sox brought them together last year.

The combination clicked and the result can be seen Saturday at the Lehman Center for the Performing Arts in the Bronx, the first stop in their “Una Sola Salsa” tour.

“When we worked together last year for a benefit for the Chicago White Sox Charity, we had great fun, and we have always had a great deal of respect for each other at the professional and personal level,” says Blades.

Speaking from Puerto Rico, Santa Rosa recalled that as a teen he called a radio station where Blades was a guest in one of his first appearances on the island in the early 1970s.

“His record wasn’t even available for sale yet, but I was already a big fan,” he says.

A couple of years later, Santa Rosa sang backup for Blades and other performers in a concert honoring Puerto Rican music legend Ismael Rivera.

“He doesn’t remember it, I bet, but I have a picture of the two of us and I am bringing it to the concert for him to see,” he says.

Santa Rosa says the concert will range over their extensive repertoires as well as some salsa standards.

Salsa aficionados recognize each headliner as the epitome of the genre’s two modes — social and romantic — hence the concert title, “Una Sola Salsa,” one single salsa.

“We both enjoy what we do very much,” says Blades, 62. “He has emphasized the romantic aspect and I have focused on urban chronicles, but I think what we both do is more broadly urban music.”

Blades says he uses “urban” not to mean the U.S. music industry label for hip hop and R&B, but to music that appeals to Latino city dwellers in the U.S. and Latin America.

Blades rose to prominence as part of the roster for Fania, the 1970s label that fostered salsa. His albums with Willie Colón, including the 1978 “Siembra,” still the top-selling salsa album of all time, are considered classics of salsa’s golden age.

Blades’ songs have most often been narratives about rough-and-tumble Latin American lives.

“What I’ve always done is music with an argument, with information and facing up to our realities,” he says.

Santa Rosa, 48, is of a generation that got its start when Blades was already established, but he, too, now is part of the old guard. He started out as a singer for such groups as Orquesta la Grande and Willie Rosario‘s orchestra, and is hailed as a master of “salsa romántica,” focused on love songs.

While some of the more hard-core salseros sometimes dismiss this style as “soft,” Santa Rosa, with a dulcet voice and great skills in the improvisatory soneo style, is considered the gold standard for love songs of substance.

The two performers say that while they continue to enjoy giving fans what they expect, this does not mean they believe that only the oldies sound good.

“Salsa is the most elitist popular music there is, because we set up standards that are impossible for new people to meet,” says Santa Rosa.

He specifically mentions La Exelencia, a salsa group from the Bronx, as an example of young guns not necessarily given a chance. But, he says, the ensemble should not worry about breakthing through. “When people like Rubén Blades and Willie Colón were coming out, the old guard condemned them as two heretic kids because they didn’t have the older orchestra sound,” Santa Rosa says.

Blades says that music lovers should not judge younger musicians because they change the classic styles. To him, all styles can coexist peacefully under the same label. “It’s like having new people move into the apartment where you used to live,” he says. “It’s still the same house.”

Blades, who left a 30-plus-year career making music and movies in 2004 for a five-year stint as minister of tourism in his native Panama, said he plans to focus for the next year on recordings, touring and doing a couple of movie roles.

He is about to start filming “Safe House” in South Africa with Denzel Washington. “I’ve always been very careful about what I do and don’t do, but as you get older you realize you need to become even pickier,” he says.

Blades, who has a master’s degree in international law from Harvard, says he hopes to begin a doctorate program in law at Columbia in 2012.

But for now, both singers say, concert performances still have plenty of appeal.

“I don’t plan to die on the road,” says Santa Rosa. “But I do want to give most of my time to singing, to have fun with the audience, to keep that long relationship going.”

BY Carolina Gonzalez