This week, at the TED conference in Vancouver, Adrianne Haslet-Davis wowed the crowd as she performed the rumba with dance partner Christian Lightner.

The audience though had no idea she had been in tears behind the scenes, afraid to dance.

"We stopped for a quick second and stood in front of the curtain before we walked out and I just started bawling," said Haslet-Davis, 33, of Boston. "Even before I got out there. The stage manager was very sweet. … [She was] throwing tissues at me. … It was like 'Wipe those tears. … We gotta do this.'"

Adrianne Haslet-Davis danced onstage at the annual TED conference this week in Vancouver. Watch for the full TED Talk and performance coming soon on www.Ted.com.

Nearly a year ago, on April 15, Haslet-Davis was at the side of husband, Adam, along the route of the Boston Marathon. The US airman just returned from Afghanistan.

"We weren't planning on going to see the marathon," she said in a previous interview with ABC News. "We just wanted to hang out together. … As we were walking towards the finish line, a bomb went off. I wrapped my arms around him, underneath his arms, around his chest, and I said: 'The next one's gonna hit.' And I buried my head in his chest. And it hit."

They were standing just a few feet away from the second bomb. Her husband suffered shrapnel to the leg. Haslet-Davis, an accomplished ballroom dancer, lost her left foot.

"We sat up and I said, 'Wait, my foot hurts.' And then he held up my foot and we both just screamed bloody murder," she told ABC News last year during a phone call from Boston Medical Center. "I didn't feel heat from it. I just felt air and then I fell to the ground."

The bombings killed three people, including an 8-year-old boy, and injured at least 200 people. Doctors later amputated Haslet-Davis' lower left leg.

She began intense rehabilitation and intense pain, both physically and emotionally. With the help of a new prosthetic leg, Haslet-Davis said she was determined to dance again.

During her TED performance this week, there was hardly a dry eye in the room.

"I felt victorious before the dance even started," she told ABC News Thursday. "I wasn't going to let this stop me. You know when I have hard days and I can't do something, I just tell myself that I'm not going to let them win and that gets me right back up on my feet."

ABC News' David Muir and Brinda Adhikari contributed to this story.

James Duncan Davidson/AP Photo