'19' going on superstar

British singer Adele begins her new tour with a sold-out show at the Somerville Theatre. (Matt sayles/associated press)

The story of Adele conquering America should have been written this past summer. That's when her debut, "19," which was already a phenomenon in her native England, was released in this country and she should have washed up on these shores with a coast-to-coast tour.

Yet she did the unthinkable: She took her time. A date at the Wilbur Theatre was canceled in September due to "problems at home," according to a statement, and none of the songs from "19" immediately caught fire on the radio. It looked as if Adele was the great artist who should, but didn't, break out in 2008, the year fellow British songbirds Leona Lewis and Duffy did just that.

Adele, after all, sounded familiar. Born Adele Adkins in London, she was a young singer-songwriter with a rich voice that was often mistaken for Amy Winehouse's. She played soulful pop music shot through with tales of love on the rocks. And she was a beautiful woman who took musical and makeup cues from another great blue-eyed soul singer: Dusty Springfield.

So how did Adele, 20, evolve from the underdog to a star who begins her new tour with a sold-out show at Somerville Theatre on Wednesday? Well, to some extent, with a little help from Sarah Palin. In October, Adele was the musical guest the night nearly 17 million viewers tuned in to "Saturday Night Live" to watch Palin's ballyhooed cameo.

"I met her backstage, and she was very nice to me," Adele says, "even though I tried not to meet her. All these Secret Service agents surrounded me, and I didn't say, 'Go Obama!' like I wanted to."

After her "SNL" appearance, Adele saw her album catapult to the No. 1 spot on iTunes and No. 11 on the Billboard 200 chart. It was a belated boost for a sublime album that really just needed some exposure. By December she was on a roll, buoyed even more by four Grammy nominations, including record of the year, song of the year, best new artist, and best female vocal performance.

Even Adele doesn't know what to make of the whirlwind year. Kanye West and Beyoncé have sung her praises, yet she still talks about how she never imagined having a career as a singer, even though it's obvious her talent is innate.

"I don't know, really," she says when asked why she's still so modest. "Loads of people want to be a pop star like Britney Spears, and it still seems unlikely that you actually can make it."

She was determined from the start, though. She graduated from the BRIT School, a performing arts institution whose alumnae include Winehouse, Lewis, Katie Melua, and Imogen Heap. She credits the school with giving her an education, "but I don't think it really affected the way I sing."

Adele talks like your typical 20-year-old: candid and unpretentious, with an accent as thick as her eyeliner. She's an unabashed fan of her peers (Laura Marling, Santogold) and the pop stars she grew up listening to (Spice Girls, Backstreet Boys). It's not the image you might expect based on "Chasing Pavements" and other sophisticated pop songs she wrote for "19."

She has mentioned Ella Fitzgerald and Etta James as influences, and like them, she has a masterful control over her instrument. The comparisons to Winehouse, who tends to sing more off the cuff, with plenty of bum notes part of the charm, melt away when you pay attention to just how measured Adele is. She doesn't attack a song so much as she inhabits it.

Adele's debut is called "19" because it's a snapshot of where she was at that age. But what a difference a year makes, especially in your teens.

"I'm still very proud of that record, but I guess I'm not really there anymore," she says of the album's heartache. "It seems like a really long time ago, and it's strange to be singing songs about someone I don't really care about anymore like that."

Adele says she has moved on from the guy who broke her heart and inspired the album, and now the tables have turned. "I think he feels like I owe him something now that the album has been successful," she says, laughing.

"I'm working on the second album, but I've still got to write the songs," she says. "I'm not in a rush to finish it, to be honest. I think it's great that people liked my first album, but I hope they'll be around in 20 years and like my fourth and fifth albums, too."

James Reed can be reached at jreed@globe.com.