The 22-year-old "Heart Wants What It Wants" hitmaker was too busy with her friends and singer Ed Sheeran to "engage" with the "Boyfriend" singer, reported Female First.
"Justin and Selena saw each other and didn't engage whatsoever. Selena was too busy enjoying herself with Ed and her girlfriends," a source said.
"Selena came with Ed and left with him shortly after Justin arrived. It was obvious she wanted to avoid any drama."
The party was thrown to celebrate Tori Kelly's new album, "Unbreakable Smile".