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It seems hard to believe that Britney Spears and Katy Perry are just meeting for the first time, but as Perry revealed on Twitter, the moment brought tears.

"OMG!!!!! I CAN'T IM CRYING," Perry wrote on Twitter after the two pop stars collided at Sunday's "Smurfs 2? premiere in Los Angeles.

Spears, 31, sings the film's theme song "Ooh La La!"

It turns out Perry, 28, also sings on the song, written by her pal and collaborator Bonnie McKee.

"Me and Bonnie secretly did some background vocals on that song," Perry told E! at the premiere. "So maybe listen for our voices."

Perry also reveled how excited she was to meet the "Toxic" singer.

"I can't wait to meet her," Perry said prior to their first encounter.

Apparently the feeling was mutual.

"So great to see you Smurfette Katy Perry!" Spears tweeted afterward.

Hinting that it may not be the last time these two collaborate, Spears added, "Can't wait for our Vegas date…"

Spears brought along her other collaborators, sons Jaden and Sean, to the premiere. The boys appear in the video for "Ooh La La!"

Keeping with the family theme, Perry brought her grandmother Ann Hudson, who previously attended the 2011 Grammy Awards, with her superstar granddaughter.