They sure love to party together.

Former reported flames Katy Perry and Diplo hit up the Sin City on Monday night for some sushi and cocktails.

Witnesses told E! News that the "Dark Horse" singer and the popular DJ had dinner at Andrea's inside Encore at Wynn. The musician pair was part of a 14-people group who were in Las Vegas to celebrate a friend's birthday.

The group reportedly started their fun night out by sampling some Wagyu beef, an assortment of sushi, ice cream and a flaming Mt. Fuji dessert at the popular celebrity hotspot.

After their hearty dinner, Perry and her friends headed to XS nightclub, where Diplo took control of the DJ booth. The 29-year-old singer and the rest of her group grabbed some cocktails and danced the night away.

Celebrity stylist Brad Goreski took to his Instagram account to share a photo of the group's dance-filled evening.

"So fun tearing up the dance floor last night with @rivfifi at @diplo in Vegas. Photobomb courtesy of @katyperry," Goreski captioned his photo.

Perry, who ended her relationship with musician John Mayer earlier in the year, was rumored to be dating her long-time friend Diplo, whose real name is Thomas Wesley Pentz.

The rumors started after the two were seen getting cozy during a Coachella Music Festival after-party in April. Eyewitnesses said the pop singer and the 35-year-old music producer were spotted together backstage during the annual outdoor concert.

In June, the two posted separate Instagram photos of their Jamaican getaway.

Perry posted her selfie in a hammock, with the caption, 'Swaying on the hammock under mango trees, fresh freckles on my face, everything irie."

Diplo also snapped a pic of his feet resting on the same hammock, but he has since deleted his Instagram picture.