Joe Jonas dating brother's ex?

Singer Joe Jonas is reportedly dating his brother Nick's ex-girlfriend.

Joe, 25, has been spending a lot of time with 19-year-old Gigi Hadid, a model who Nick Jonas, 22, romanced before dating Olivia Culpo, reported Radar Online.

"Joe and Gigi have hung out a few times this week actually. They have visited a museum together and even went to the park together on Thursday.

"Nick and Gigi (had) an ongoing thing. The fact that Joe and Gigi are hanging out now is just strange," a source said.