Katy Perry and Gerard Butler had "intense chemistry" at a recent event.
The two stars have been linked in the past and are understood to have gone on several dates after Katy split from her ex-husband Russell Brand.
They both attended the prestigious White House Correspondents' Dinner late last month and surprised many with their flirty display at an event held afterwards.
"They ended up sitting on the upstairs terrace talking and laughing. Katy definitely looked happy. They left separately, but that didn't stop people from talking. The chemistry was intense!" a source told Heat magazine.
The glitzy annual event started in 1920 as a way for journalists who covered White House news to meet and share stories. It has now progressed with many of Hollywood's A-list attending.
Katy and Gerard went to both the meal and the after-party and apparently spent a good deal of time eyeing each other at both events.
"They were really flirty all night," the source explained. "It started at dinner. Gerard was there with Piers Morgan and Katy kept drifting to their table. Everyone was mingling at first so no one took much notice, it wasn't until the Vanity Fair after-party that they really stood out."
Katy split from John Mayer earlier this year after an on/off relationship. Ladies' man Gerard is thought to be romancing Madalina Ghenea.