Harris, 32, who split from Taylor Swift in May after 15 months of dating was spotted partying with Scherzinger, 38, reported E! online.
"They're casual friends, and if they see each other at a club or party they will chill. They are not hooking up or hanging out. Calvin isn't rebounding with anyone at this time," a source said.
The Scottish DJ is said to be hurt by Swift's new romance,
which came out just days after the musician announced his break-up from her.