Lily Collins: 'Seventeen' Magazine September Cover Party!

Lily Collins shows off her flat tummy while attending her Seventeen Magazine Cover Party held at Barnes & Noble Union Square on Tuesday (August 6) in New York City.

The 24-year-old actress was seen signing copies of the magazine’s September 2013 issue for fans, who attended the event.

PHOTOS: Check out the latest pics of Lily Collins

The day before, Lily sported a beautiful yellow dress while promoting her latest film The Mortal Instruments: City of Bones on Late Night with Jimmy Fallon.

“The moment that this character was conceived of, we knew that we wanted someone who had an otherworldly look. Who had an innocence and poise and a quiet intelligence that would almost suggest she is not from this world. I had met Lily years ago and instantly thought of her,” Bryce Dallas Howard recently told Vanity Fair about casting Lily in M83‘s music video “Claudia Lewis.” Watch the video below!