Finally, Gwen grabs the cameraman's phone and the surprise goes off without a hitch. "The look on the girls' faces when they walk through the Jetway and see the Backstreet Boys is priceless," Sarah says.

"I only remember little bits and pieces because there was so much excitement and nerves ," Gwen says. "It was a huge [surprise] to pull off, and I think it was amazing."

Catch up with the Backstreet Boys