st. jude children's research hospital we won't stop until no child dies from cancer. this september, please join st. jude in our fight to end childhood cancer. okay, what is this? it' s chewy. really icy. wooh. that' s intense! it just hits you. its gum. no. it' s totally a mint! it' s disappearing as i am chewing it. where did it go? it' s not a gum. not a mint. it' s a totally new cool. [ cheers and applause ] >> jimmy: our next guest became the youngest artist in five years to hit number one on the billboard 200 chart with his debut album, "hand written." performing his platinum single "stitches", with a little help from the roots, give it up for shawn mendes! [ cheers and applause ] i thought that i'd been hurt before but no one's ever left me quite this sore your words cut deeper than a knife now i need someone to breathe me back to life got a feeling that i'm going under but i know that i'll make it out alive if i quit calling you my lover move on you watch me bleed until i can't breathe shaking falling onto my knees and now that i'm without your kisses i'll be needing stitches tripping over myself aching begging you to come help and now that i'm without your k