Flirty British sensation Lily Allen donned her best party dress at New York City's Hiro Ballroom for her grand American entrance. Preceded by a three-piece horn section -- each wearing Allen's official tour shirt -- Allen clicked onto the stage dressed Meatpacking District-perfect, with stilettos on her feet and a champagne flute in hand. The notoriously brash singer seemed to have lost a bit of her confidence, as she looked wide-eyed upon the packed ballroom, quietly crooning opening song "LDN" into the mic. As the show went on, though, Allen gathered back some of her courage, batting her big eyelashes at the crowd, sassily popping her hips to her version of 50 Cent's "Window Shopper" (which she calls "Nan, You're a Window Shopper"), and following up the ballad "Littlest Things" with the epilogue: "You'd be pleased to know that the guy I wrote that song about, I'm back together with now. So it worked." Towards the end of her set, she'd worked over the crowd as well, even prompting a sing-along to her No. 1 U.K. single, "Smile." STORY BY ALYSSA RASHBAUM. PHOTOS BY JULIA SIMON

We asked: Given that Lily Allen's single is called "Smile," we want to know what makes you smile? COMMENT

Name: Paul Hinman
Age: 23
Hometown: Brooklyn, NY
Occupation: Law school student
"Lily Allen, mostly."

Name: Kelly Reeves
Age: 23
Hometown: Atlanta, GA
Occupation: Grassroots music marketer
"Kittens."

Name: Michael Atkinson
Age: 23
Hometown: Philadelphia, PA
Occupation: Lifestyle marketing
"Sleeping with hobos."

Name: Kenton Langstroth
Age: 23
Hometown: Ft. Lauderdale, FL
Occupation: "I work for the man."
"A beautiful girl singing."

Name: Danielle Avisser
Age: 24
Hometown: Washington, D.C.
Occupation: Graduate of NYU
"Boys."

Name: Miri Reginiano
Age: 25
Hometown: Israel
Occupation: Fashion design student
"Beer."

Name: Andrew Pamtoja
Age: 23
Hometown: Brooklyn, NY
Occupation: Editor
"My girlfriend."

Name: Mimi Lin
Age: 25
Hometown: Boston, MA
Occupation: Director, event and marketing production
"Happy people and good music."

Name: Liz Tan
Age: 22
Hometown: New York, NY
Occupation: Graphic designer
"Chocolate."

Name: Daniel Merriweather
Age: 24
Hometown: Melbourne, Australia
Occupation: Singer
"Music."

Name: Alexandra Hay
Age: 24
Hometown: Australia
Occupation: Advertising
"Good times, good music."

Name: Wesley Gott
Age: 26
Hometown: Atlanta, GA
Occupation: Typographer
"Vanilla ice cream."

Allen accepts flowers, delivers encore

Lily Allen's enthusiastic horn section

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