updated 08/14/2011 AT 2:00 PM ET
•originally published 08/14/2011 AT 3:15 PM ET
Joe Jonas got a jumpstart on his 22nd birthday celebrations in Las Vegas – in a big way.
Starting off Saturday, Jonas, whose actual birthday is Aug. 15, caused a splash at Liquid Pool Lounge when he spent the afternoon poolside in a VIP cabana with pals.
“Female fans surrounded the area, trying to get a glimpse of [Joe] in his bathing suit,” a source tells PEOPLE.
Following his fun in the sun, Jonas and his entourage then headed to the Bellagio Hotel where they were treated to a meal from Akira Back, the executive chef at Yellowtail Japanese Restaurant & Lounge.