Monday night, Gigi and new flame Joe Jonas hit up L.A. hotspot The h.wood Group's The Nice Guy, where they hung out with Bella and her boyfriend the Weeknd – and pal Taylor Swift even got in on the action.
"The entire group hung out at a table together," an onlooker tells PEOPLE. "Joe and Gigi cuddled but weren't over-the-top, and Taylor was friendly and bubbly while socializing with her friends."
Meanwhile, Bella and her beau were "super cute" together, the onlooker adds. And the Weeknd had ample reason to celebrate: He topped the Billboard Hot 100 chart for the first time with his single "Can't Feel My Face."
Early Tuesday morning, Jonas, who turns 26 on Saturday, posted a giant group shot (including his girlfriend, her sister and Swift) at a soccer field, seemingly getting some pre-birthday celebration in with pals.
"Thank you for the best surprise ever. I love All these people. #megasquad," the former Jonas Brother captioned the photo.
Reporting by MELODY CHIU