"I'm just going to sing my heart out and I can't believe I'm performing. It hasn't really hit me yet," he said before taking the stage.
Smith also started his evening out right, Tweeting a picture with Beyoncé when he arrived at the highly anticipated event.
You're gonna wanna open this... pic.twitter.com/ZOtQglCJw8— SAM SMITH (@samsmithworld) August 25, 2014
And after his performance (see it below), Twitter blew up with praise for the singer.
But the cheering crowds don't faze Smith – especially when he's in America. "American audiences are louder, which I really like. I think they should be," he told reporters.
"It's early days, everyone could just piss off and leave me, but I feel like these people are going to stay with me. I feel like audiences are going to stick with me. I hope so."
If Adele and Sam Smith did a collab together I'd probably be in my feelings for some weeks.— Jae. (@jaefromvine) August 25, 2014
I want to bottle sam smith's voice in a jar and just keep it beside me— (@louberrytea) August 25, 2014
if you don't think sam smith is an angel then you are 112% irrelevant— (@Figgalicious14) August 25, 2014
Listening to Sam Smith will have you missing your best friend's ex for them.— Don Rob™ (@ImRobGodDammit) August 25, 2014
sam smith's voice should be a candle scent— ☪Casey☪ (@CASEadillaxo) August 25, 2014
Take one look at this adorable, mid-singing smile and tell us you don't feel the same way.
Additional reporting by CHRISTINA DUGAN