A good boyfriend will accompany you to a party, but a great boyfriend will watch your cats while you hit the town solo. Taylor Swift was part of the celeb-heavy turnout at Joe Jonas' surprise birthday bash. The shindig was organized by Jonas' girlfriend Gigi Hadid. Since a boring bar is no place for a Jonas-worthy celebration, the festivities were held at L.A.'s StubHub Center. The stadium proved to be a great setting for photo ops, and pics of the partygoers popped up on model Devon Windsor's Instagram, as well as on Jonas' own. Notably absent from the pics? Calvin Harris. Swift's boyfriend didn't have a completely uneventful night, though. The Scottish music impresario posted Snapchats proving he had his hands full with Meredith and Olivia, Swift's adorable kitties. Either way, both stars seem to have had an epic Monday night. Check out the proof below.