It looks like Katy Perry doesn't want John Mayer to be "The One That Got Away."

The on-again, off-again pair were photographed together again on Tuesday night, where Mayer celebrated his 35th birthday with about a dozen pals, including 27-year-old Perry, at downtown NYC eatery Freeman's.

PHOTOS: John Mayer's busy dating history

Decked in a ladylike floral dress, Perry sat right next to the birthday boy during the low-key meal, which went on for several hours; Mayer's dad, Richard, was also on hand for the night.

"It was a very tame and civil," an eyewitness tells Us Weekly. "They talked and laughed but nobody got crazy. Everyone looked like they were having fun. John seemed happy."

PHOTOS: Katy's wildest video looks

Adds another observer: "John had a great time. He's matured."

Before Tuesday's festivities, the twosome were spotted spending time together in the Big Apple over the weekend: Mayer supported Perry during a private concert at Best Buy Theater in NYC's Times Square on Sunday, followed by an intimate dinner at Pearl Restaurant and cocktails at Soho House.

PHOTOS: Katy's hair through the years

Mayer first began dating the recently divorced "Wide Awake" singer back in June. But after a couple months of casual dating, the two parted ways in late August. "She is making it seem like it wasn't serious with John, but she is hurt," a source told Us at the time.

Now reunited, a source explains to Us that Perry "believes she can change him."

This article originally appeared on John Mayer Reunites With Katy Perry to Celebrate His 35th Birthday