I don’t speak Portuguese. I have never spoken Portuguese. But for one magical night in Back Bay, I did.

At least, that’s how I felt at John Hancock Hall on Friday. Sitting in an auditorium filled with people who shared a common ancestry and culture, laughing with each other in syllables that I could barely follow, there was a nagging sense—unfounded but true—that I was a stranger, an outsider.

As the lights went down, I tried to suppress that feeling of unease, of un-belonging. What was I doing here?

Then the lights came up, and Seu Jorge and Daniel Jobim took the stage to thunderous applause. Without so much as an introduction, the music started as if they and we and I had been sitting there our entire lives. I felt right at home.

Seu Jorge and Daniel Jobim are perhaps unknown to American audiences, but they are titans in Brazil. The duo is currently touring the United States, commemorating the legacy of Antonio Carlos Jobim, Daniel’s grandfather—who also happens to be the most famous Brazilian musician of all time.

The elder Jobim pioneered bossa nova, the genre of lounge jazz that took the world by storm in the 1960s with its subdued samba vocals and soft acoustic melodies. Even those who don’t know the genre in as many words can hum “The Girl from Ipanema,” Frank Sinatra’s iconic meditation on beauty, love, and sensuality—which, of course, was written by Jobim about his hometown of Rio de Janeiro.

Bossa nova does not have much of a tradition in Massachusetts, which is not known for its sandy beaches and tropical weather. But when you realize that the Greater Boston area has the highest proportion of Brazilian Americans in the country—approximately 57,000 strong, according to the Migration Policy Institute—the visit becomes perfectly sensible.

At the piano sits Daniel Jobim. A portly man in a dark suit and straw hat, he gives the air of a man raised in sophistication but rooted in humility—a walking, effortless paradox. He is a picture of his grandfather, who kept his boyish looks all his life. Before the applause can fully die down, he takes to the ivory and starts playing “Wave,” a late-period Jobim earworm that rises and falls and rises again.

Seu Jorge gives the impression of being rougher around the edges. Despite his unassuming outfit—an all-tan suit, somewhat drab, ornamented only by silver sunglasses that flash under the spotlights—there is a power to him the moment he takes the microphone. His voice is coarse, even forceful, as he belts “Luiza,” a Jobim torch song dripping with the fierce anguish and pain of unrequited love.

Or that’s what it felt like, anyway.

The English speakers among the audience might recognize Seu Jorge for his acting credits. In Wes Anderson’s film “The Life Aquatic with Steve Zissou,” he plays opposite Bill Murray and Owen Wilson as the ship’s resident diver-guitarist. Seu Jorge also stars in the gritty crime flick “City of God,” set in the poverty-stricken favelas where the singer spent his youth.

Seu Jorge is not usually a bossa nova singer. To Brazilian audiences, he’s a funk-rock singer who does David Bowie covers (to put it crudely). But on Friday night, he was the perfect pairing for Jobim. It was as if Prince had done a duet with Johnny Cash’s grandson—crazy enough to work.

Eventually, the duo had enough foreplay and, to the crowd’s delight, launched into the Jobim classics: “Só Danço Samba,” with its cascading whimsy, a sort of percussive, xylophonic tip-tap-tip; “Samba do Avião,” a heartfelt, ethereal longing for the comforting arms of Rio de Janeiro; and “Dindi,” a tender, flowery ode first popularized by Frank Sinatra (in his native English).

While recording his collaboration with the elder Jobim in 1967, Sinatra, who made his name belting powerful ballads in the vein of “New York, New York,” is said to have quipped that he had never sung so softly before. One critic wrote that Sinatra’s natural voice was “a rougher grain that he brilliantly scrubs smooth.” That’s the beauty of bossa nova—it captures a fleeting softness and tenderness in a harsh, unforgiving world.

So, for a voice that is said to be inimitable, Seu Jorge’s Sinatra impression wasn’t half bad.

Jobim and Seu Jorge traded off for “Desafinado”—Jobim handled the lead vocals, while Seu Jorge took a guitar from offstage (the spitting image of his “Life Aquatic” character). Seu Jorge continued showing off his multi-instrumental talents with “Corcovado,” adding a haunting flute accompaniment to the piercing melody, and with “Água de Beber,” lending a pulsing tambourine.

As the classics piled on, audience members tapped their feet and pursed their lips, rolling their heads, sometimes gingerly, sometimes violently. Energy surged through the crowd as a thousand people hummed and tapped and moved as one. When the set list came to “Chega de Saudade”—the song that, more than nearly any other, has become the anthem of bossa nova—Seu Jorge extended his microphone to the audience.

At once, the impromptu chorus delivered a hushed, impassioned, united roar. It was a collective, subdued whisper, with the expressiveness of a poet and the power of a steamroller.

Seu Jorge and Daniel Jobim—and the man they owe it to, the long-gone Antonio Carlos—filled a dingy auditorium in Back Bay with one singular nation in song, united in joy and sadness and longing for a homeland far, far away.

“Chega de saudade / A realidade é que sem ele não há paz / Não há beleza é só tristeza e a melancolia / Que não sai de mim, não sai de mim, não sai.”

What does that mean, exactly? I could guess, but I don’t really know.

That is to say I don’t know the words exactly. I know the feeling, the swelling of joy and anger and sadness, the intangible sense of beauty and love come and gone again.

After a painfully obvious encore, the pair came back for Antonio Carlos Jobim’s magnum opus: “The Girl from Ipanema.” Once again, the dingy auditorium was filled with song: Jobim on the piano, Seu Jorge conducting the crowd, and a thousand people—Brazilian, Americans, and everything in between—singing as if they were millions.

Pearl-white sand, foaming waves, and the salt of a summer’s breeze. That’s bossa nova.

Jobim, in an interview with The Boston Globe earlier this month, said that while his grandfather’s music is not as popular as it was 50 years ago, it also isn’t made “for understanding.”

“It’s for feeling,” he said. “Everyone can feel his music.”