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(Yahoo!) - Did John Mayer pass the best friend test?

Katy Perry and Rihanna had dinner with a group of pals on Monday at The Lion, a fitting restaurant to celebrate at since Perry spent the day promoting her new single "Roar."

"She. X She. ?#KatyAnna?#RIHunited," RiRi, 25, tweeted along with the above picture.

Also in play (and who probably deserves a photo credit on Instagram) was Katy's boyfriend. Witnesses tell omg! the trio sat together upstairs and appeared to be in "great spirits."

"They looked like they were having a blast," a diner tells omg!. "Katy and Rihanna were laughing a lot and it looked like John could definitely keep up, too."

Mayer, 35, and Perry, 28, were already at the eatery when the "Stay" singer swung by.

"John and Katy were really cute together," adds the onlooker. "He was definitely very attentive. They looked happy."

Maybe the third time really is the charm for the reconciled lovebirds. Katy and John just released a duet, "Who You Love," from Mayer's upcoming album "Paradise Valley."

Some sample lyrics?

John sings: "My girl, she ain't the one that I saw coming / Sometimes I don't know which way to go / And I tried to run before but I'm not running anymore."

"My boy, he ain't the one that I saw coming / And some have said his heart's too hard to hold," Perry croons. "And he takes a little time but you should see him when he shines / Cuz you never want to let the feeling go."

After a couple of breakups, Perry and Mayer reunited again in May and have been going strong ever since.