tonight mendes lets abc's chris connelly into the whirl wind his life has now become. >> reporter: the seen screams of young female pop music fans may be familiar -- >> i hope you enjoy the show, guys. >> reporter: the face and the name that they're screaming for may not. i've been hurt before >> reporter: this is sean mendes, a 17-year-old singer/songwriter, on his own onstage with just his voice, his guitar, and that smile. this canadian can draw a crowd of thousands in los angeles. you watch me >> reporter: watching him play such wide-eyed hits as "stitches." >> when you're out there and your fans sing it back to you what goes through your heart? >> it's the best. there's feeling like having your fans singing your song back to you. >> he's really hot, he's really hot. >> i'm sorry it took so long. >> reporter: it's the climax to a full day which began hours earlier. >> reporter: on the go sean serenading a smaller group, the fortunate ones at his vip preshow. >> to see him in person is just like -- the best. >> i was trying to get my phone to take a picture and i couldn't do it. >>

and it kind of came true. ♪ you watch me >> reporter: for "nightline," chris connelly in los angeles.manhattan. thousands lining the streets just to get a glimpse of the man himself. and a waxed statue as well. but i couldn't do it on my own. i needed help and chantix was there. and i did it. along with support, chantix (varenicline) is proven to help people quit smoking. it reduces the urge to smoke. some people had changes in behavior, thinking or mood, hostility, agitation, depressed mood and suicidal thoughts or actions while taking or after stopping chantix. some had seizures while taking chantix. if you have any of these, stop chantix and call your doctor right away. tell your doctor about any history of mental health problems, which could get worse or of seizures. don't take chantix if you've had a serious allergic or skin reaction to it. if have these, stop chantix and call your doctor right away as some can be life-threatening. tell your doctor if you have heart or blood vessel problems, or develop new or worse symptoms. get medical help right away if you have symptoms of a h