The 22-year-old actress' on-off boyfriend Robert Pattinson is currently shooting a film in Australia, leading the actress to attend Twilight co-star Taylor Lautner's recent birthday celebration alone, reported Digital Spy.
An insider said that Stewart got very close to model-actor Patrick at the party.
"She was creeping on Patrick big time. People were saying they should get a room because the energy between them was so hot," a source said.
Patrick was previously linked to Taylor Swift, although those romantic rumours were strongly denied by Swift.
Stewart and Pattinson famously had romantic troubles last year due to the actress admitting to a fling with her married Snow White and the Huntsman director Rupert Sanders.
The couple later reunited, but there have been reports of renewed relationship trouble in recent months.