The former couple, who broke up in 2008, were spotted together following actress Jaime King's baby shower that Swift hosted on Sunday.
The 25-year-old "Blank Space" singer joined Jonas, 25, and his rumored new girlfriend Gigi Hadid, 20, at Plan Check in Los Angeles, but Swift's beau Calvin Harris was not seen at the table. Several reports say that the musician was with the group earlier that day during King's shower at West Hollywood's SoHo House.
While Jonas and Hadid -- who's also friends with Swift -- have yet to confirm their relationship, they have been caught canoodling on numerous occasions. Earlier this month, the two were seen being "very affectionate with one another" at the Bowery Hotel Bar in New York City. They were also spotted getting quite cozy at the CFDA Awards.
The model called it quits from Cody Simpson just last month.