On-again couple Katy Perry and John Mayer were heating up the Big Apple on Monday night.

In town to promote her upcoming album "Prism," Perry joined her beau and a group of pals, including BFF Rihanna, for drinks and dinner at The Lion in the West Village.

"She and John were affectionate," a spy-witness dished. "John [kept] Katy close with his arm around her while they stood at the bar."

After grabbing some beverages at the bar, the pair -- who duet on the new tune "Who You Love" -- headed upstairs to The Lion's private room for their meal.

More than halfway through dinner, RiRi joined the 15-person party, causing a "flurry of flashes" from the photogs outside. Once Rihanna got upstairs, she "sat next to John and Katy to catch up."

Jake's 58 to get bigger parking lot ... Police chief's new book ... Previewing Yanks/Rays Game 3 Credit: Newsday

Fire department volunteer removed after Facebook comment ... Lindenhurst hit-and-run victim identified ... Jake's 58 to get bigger parking lot ... Working Moms: Navigating loss

Jake's 58 to get bigger parking lot ... Police chief's new book ... Previewing Yanks/Rays Game 3 Credit: Newsday

Fire department volunteer removed after Facebook comment ... Lindenhurst hit-and-run victim identified ... Jake's 58 to get bigger parking lot ... Working Moms: Navigating loss

Subscribe

Unlimited Digital AccessOnly 25¢for 6 months

SUBSCRIBESALE ENDS SOON | CANCEL ANYTIME