It looks like Katy Perry and John Mayer are ready to make their romance more than just a summer fling!

The totally on-again pair left Freeman's restaurant in New York City together after celebrating John's 35th birthday with some friends Tuesday night. Joined by about a dozen friends, Katy spent the evening sitting next to John, an eyewitness tells Us Weekly. "Everyone looked like they were having fun," the source says. "John seemed happy."

Related Article: Katy Perry is Billboard's Woman of the Year!

Not convinced? This wasn't their only outing together recently! They were photographed together earlier in the day after a lunch date at ABC Kitchen, and John attended Katy's private NYC concert on Sunday evening before taking her out to an "intimate" dinner afterwards.

Although the couple casually dated during the summer, ending things in August, it looks like they're taking it more seriously this time around -- can it last?!

Do you like John and Katy as a couple?!

Photos Courtesy of: Getty Images