The 21-year-old youngest Jonas Brother served as a delivery boy on March 28 for customers who ordered alcohol via Saucey app where he was one of the investors.
The ex-Disney star poured wine, did shots, and grabbed a guitar for impromptu performances.
"Pure craziness and fun times last night in Los Angeles. Met some awesome people. Thanks, @SauceyApp for it!" he tweeted.
"Speechless. Nick Jonas in our apartment, delivering me wine and singing me songs. My life has been made," one fan wrote.