Singer Luis Fonsi's hair is so black it gleams. He has thick brown eyebrows, deep brown eyes, and his skin is tanned a rich caramel. But for all his dark features, his eyes shine so vibrantly that the impression he gives is one of brightness.

And now, his career is brighter than ever.

Fonsi is in need of all the radiance he can muster on a recent weekday amid the chaos of a rehearsal at BankUnited Center in Coral Gables for Univision's hugely popular pop-culture awards show Premios Juventud. Fighting flu, he has hauled himself from bed to get here, and the show's revered producer Cisco Suarez is enthusiastically explaining the indoor waterfall he's arranged for the premiere of Llueve Por Dentro (It's Raining Inside), the third single off Fonsi's blockbuster album Palabras del Silencio.

``You're going to get soaked big time!'' Suarez says. ``Today?'' Fonsi responds, eyes wide. ``But I've got interviews. I'm sick.''

``Today, tomorrow, every day!'' Suarez says gleefully.

After some negotiating, Fonsi won't get drenched that morning, though Suarez still grumbles that the singer should have brought a change of clothes. But with 13 Juventud nominations capping off his biggest year since he started a decade ago, Fonsi (short for Alfonso, his middle name) can push back a little, even with a media titan like Univision.

For years, Fonsi's lightweight pop ballads had earned him moderate success but little artistic recognition. That situation has changed with Palabras, his most musically substantial and commercially successful recording yet, earning him a favorable mention in The New York Times and his first Grammy nomination. The album's lead single, No Me Doy Por Vencido (I'm Not Giving Up), co-written by Fonsi, is a moving anthem of determined hope that struck a chord in a year when there were plenty of reasons to give up and spent 30 weeks at the top of the Latin radio charts.

``You can tell he's feeling every word,'' Suarez says. ``It's what he projects, and you either have it, or you don't. I can slap a camera on him, and he'll always grab the audience.''

HIS HARDSHIPS

But Fonsi, 31, is not one to strut over his triumphs. Although his life seems all star-powered ease these days, he has endured personal trials that have made him see music as more than a vehicle for fun and fame. Five years ago, just as he'd arrived at North Miami's Criteria studios to start recording Palabras' predecessor, Paso a Paso, he got a call from the sister of his fiancee, actress Adamari Lopez, to tell him that Lopez had tested positive for breast cancer.

Fonsi took a cab across town (his car had gotten a flat tire on the way to the studio) to South Beach, where Lopez was filming a show. ``As soon as I showed up she knew,'' he says. ``We cried it out, hugged it out. She's a lot stronger than I am. I did what a fiance is supposed to do -- I stood by her. I threw her parties after every chemo treatment. It was the least I could do. She got through it. I think it made us stronger.''

Fonsi's previous albums had been bubbly or romantic pop, but the couple's struggle with cancer cast a much darker mood over Paso a Paso (Step by Step). ``Though I have faith, pain gnaws me,'' Fonsi sings in the title track, written two days after he got the news. ``And I hide my fear under the pillow.''

Palabras is as much marked by relief to be past that painful time as Paso was etched by it. This is Fonsi's most mature, and relaxed, record yet. ``I hate cliches, but this record is the calm after the storm,`` he says. ``All that dark period is over. She's healthy. Our family is great. I've learned and grown as a songwriter. All these things have enriched me.''

HE'S MATURED

Sebastian Krys, who produced Paso and part of Palabras, says those trials forced Fonsi to grow personally and musically.

``This pushed him to understand what's really important and what's not,'' Krys says. ``He got more comfortable with who he was. It allowed him to open up more and take more risks. Before, he was the kind of guy who would go sky-diving and bungee-jumping, all this on-the-edge stuff, but in music he was always taking the safe route. In the last few years, he let go a little and didn't always take the safe route as a songwriter and musician. He understood what he brought to the table, and he got more comfortable defending what he wanted to defend.''

Says Fonsi, ``Now I'm more concerned about the message and the musicality, not the perfection of the vocal, or my outfit or the choreography.''

Artistic stance or not, Fonsi remains practical about the demands of his job. More than many stars, he seems happily normal, humming other people's songs, greeting adoring make-up artists, camera and sound technicians, or prowling around TV hosts with the same smile and slap on the back. He cheerfully goes through the required motions inside the Univision promotional machine, posing for photos with people's children, doing radio and Internet interviews.

As he tapes a segment promoting Nuestra Navidad, a Univision Christmas special filmed at St. Jude Children's Research Hospital in Memphis, he struggles a bit with the Spanish on the prompter. ``OK, OK, pronunciate!'' he urges himself. ``Here we go!''

Producer David Naranjo, who also works with Gloria and Emilio Estefan, says Gloria wants to go to Fonsi's Aug. 22 concert at the James L. Knight Center. ``Gloria?'' Fonsi says, winking. ``I gotta see if I can arrange that.''

He is too conscious of how long it took him to get here to glory much in his status. ``It's been step by step,'' he says. ``It's not like, `Oh, I'm on top of the world. I'm No. 1.' I've worked my butt off. That keeps my feet on the ground -- I'm the same Luis Fonsi onstage and at home cooking an omelette in basketball shorts.''

PATH TO FAME

His happily normal, middle-class background also helps keep him grounded. His parents work in marketing and moved their family (he has two siblings) from Puerto Rico to Orlando when Fonsi was 10. In high school, he sang with a group that included future N'Sync member Joey Fatone, then went on to get a music degree at Florida State University. He quickly landed a contract with Universal Latino and released his first album in 1998.

The experience with cancer pushed Fonsi and Lopez, now his wife, into work with related charities. Lopez supports campaigns against breast cancer, and Fonsi has become known in music circles for working with seriously ill children. He visits hospitals twice a month, and his office often gets calls from families with sick children; on this afternoon, Fonsi is going to visit a 10-year-old boy about to have brain surgery. He's been twice to St. Jude Hospital in Memphis, which treats children with cancer from all over the world free of charge, and has performed twice at the FedEx/St. Jude Angels & Stars Gala, which raises money for the hospital.

Evelyn Homs, a marketing director for St. Jude's fundraising efforts, says Fonsi spent hours playing with and talking to the children and their families.

``I never cried so hard in my life,'' Fonsi says. ``Part of our job as quote-unquote `celebrities' is that we can gather people around things that are important. I think it should be a requisite -- there should be a clause in the contract that you have to give back.''