As a child, George Dennehy questioned why God had him born armless and left in a Romanian orphanage as a newborn by parents who feared their small village wouldn't accept him.

Dennehy, 18, of Ashland, Va., said Tuesday he believes his answer has come. He not only opened for alt-rockers the Goo Goo Dolls on the main stage at Musikfest, but also sang and accompanied the band on its song "Iris" by playing his guitar with his feet.

About two weeks ago, a friend persuaded Dennehy to post a video of himself playing the song on the online social news site Reddit. Within 10 days, it had gone viral, getting 400,000 hits, becoming one of Reddit's top views and being duplicated on far-flung websites in Australia and elsewhere.

"When the comments [on the posting] started coming in Japanese, I said, 'We're there!' " said Dennehy's father, Michael.

Among those who liked the video was Goo Goo Dolls drummer Mike Malinin, who Dennehy said reached out to him on Twitter and asked that he contact him. It was in that conversation the group offered him the chance to open for and play with them.

"I was overwhelmed," said Dennehy, who recently graduated from high school. "I was like, 'This is cool.' "

Malinin said he became aware of Dennehy when friends started emailing him, saying he needed to see the video.

"it was just amazing and I sent it to the others. [Singer] John Rzeznik wrote back and told me to contact him and see if he'd play with us," Malinin said. He suggested the Musikfest show because it was close to Virginia.

"It's pretty inspiring to see him," Rzeznik said. "He's a great kid. I just think it's an amazing achievement."

Dennehy's parents, who adopted him at a year old, have 12 children — nine adopted and most with special needs. He said three of his siblings play classical instruments, and when he was 8, he started playing cello. His teacher, who has arms, learned to play with her feet so she could teach him.

He said he believes he's the only known performer in the world who plays a classical stringed instrument with his feet.

But like many musical teen boys, Dennehy gravitated toward guitar and taught himself to play. The instrument sits on a flat surface and he strums and picks the strings with one foot while manipulating the frets with the other. Making things even harder, he plays left-footed, meaning his guitar is upside down from its traditional playing position.

In February, he won the "Richmond's Got Talent" competition held during halftime at college basketball games in Virginia.

At a news conference at Musikfest on Tuesday, he flipped sheet music pages with his toes and even used his toes to clamp a capo on his guitar's neck to raise its pitch. "These capos and these toes are a challenge, but it works," he said with a laugh.

He performed soulful versions of the Goo Dolls' "Slide," the Calling's "Wherever You Will Go" and Howie Day's "Collide." But he said he chose "Iris" for the video because it's "one of my favorite songs ever." He said the Goo Goo Dolls is one of his favorite bands.

Dennehy met with the band and rehearsed with it at its sound check Tuesday morning. He said Musikfest will be the only date he plays with the group, but said his quick fame has brought a lot of opportunities.

He has started to perform at his church and a local farmers market and is writing songs. On Thursday he will go to a studio to record for the first time. A producer has asked him to record an EP.

A Romanian television station wants him to perform and meet his biological parents. Dennehy's adoptive mother, Sharon, said the parents loved him and were reluctant to give him up, but felt it would be best for him.

Dennehy said he wants to learn banjo and mandolin, and "go wherever the Lord leads me." He has even put off college.

"It gives people inspiration — that there's no reason not to follow your dreams and chase after what you want," Dennehy said. "As a kid, I would wonder why God would make me like this. As I get older, I understand there is a purpose. I believe he made me this way on purpose — and for this purpose."