Last week, Justin Bieber, 21, serenaded ex-girlfriend Selena Gomez, 23, at a hotel lobby bar, and the former couple was also photographed strolling together afterwards, but a source close to the singers tells PEOPLE they are not a couple.
"They care about each other and miss each other, but they're not getting back together right now," says the insider.
Gomez – who performed her latest single "Same Old Love" at the American Music Awards on Sunday – attended Bieber's afterparty at the h.Wood Group's The Nice Guy in Los Angeles, where the two were "just friendly," says an onlooker.
The "Sorry" singer was photographed leaving the party with singer Halsey, with whom he performed their duet "The Feeling" from his new album Purpose on Today on Wednesday.
Bieber also had a big night at the AMAs, where he closed out the show with a wet and wild performance.
"Kourtney [Kardashian] and Kylie [Jenner] brought a cake out for Justin to celebrate his number one album," adds the onlooker at the party, where Gigi Hadid and the guys of One Direction also made an appearance.