Janet Jackson celebrated the end of the US leg of her “State of the World” tour at a private bash at STK Atlanta with her producer ex, Jermaine Dupri.

“They arrived together right after the show. He was dressed in a long hooded cloak. It seemed like he was trying to fly under the radar,” a spy told us.

We’re told the divorcing singer and Dupri spent the evening together seated in the VIP area. Another witness said Jackson was in high spirits and was “thrilled the restaurant made vegan options for her. She was super friendly, saying hi to everyone.”

Big Boi from Outkast was also spotted with his wife at the party.

Jackson’s rep did not comment.