The 24-year-old American actress kissed the 27-year-old Canadian singer in a photo Friday while attending a birthday party for the rapper Belly in Los Angeles, according to People.
Sources told the magazine Gomez and The Weeknd, who shared the picture the next day, remained "playful and affectionate" throughout the night. The pair mingled with such stars as Drake, Amber Rose, Ashlee Simpson and Evan Ross.
"Selena and The Weeknd were very sweet together and mellow," an insider added to E! News. "They took selfies and then cuddled up together. They were really focused on each other and look very serious and in love."
Gomez and The Weeknd, born Abel Tesfaye, were first linked in January following the singer's split from model Bella Hadid. The couple rented out a movie theater for a date night in March during a trip to The Weeknd's hometown of Toronto.
"They both didn't expect this to go as fast as it has, but it's fine by them," a source recently told E! News. "They are both happy and have a great connection, physically and mentally."
Gomez last released the album Revival in 2015, and attended the premiere of her Netflix series, 13 Reasons Why, last week. The Weeknd released the album Starboy in November.