Hmm, okay! Not a whole lot of info.. nothing really confirmed... sounds cool tho...
http://www.deccanchronicle.com/chann...amil-movie-903
Katy Perry to sizzle in a Tamil movie?
Looks like the American hottie and pop singer Katy Perry, who wowed the Chennai audience at the recent IPL 5 opening ceremony, will be roped in for a Tamil film! Can’t believe it?
But that’s the hot buzz going around K’town.
Director Prabhu Raja Chozhan, a former assistant of ace filmmaker Shankar, who is making his debut with Karuppampatti, is approaching Perry for a disco number with the peppy lines Naughty Raja Raja.
It has been rendered by none other than Bollywood’s disco guru Bappi Lahiri. The movie features Ajmal Ameer and Aparna Bajpai in the lead, and has music by Kannan of Tamil Padam fame.
Talking to DC, director Prabhu said, “It’s a film set between 1970 and the present. Ajmal plays the dual role of a father and son. He plays an NRI who comes to Chennai from France in search of his roots. The Naughty Raja number written by Kabilan and set in the 80s appears as a stage song with thousands of live audience.
"The song has turned out to be so good that we felt that an international performer would be the right choice to make it a visual extravaganza. We are officially working through known sources to rope in Katy and hope to bring her on board.”
The film has been shot extensively in Paris.
(Hehe, kidding.)
Indicates that things are already starting up behind the scenes for Katys next album. 
I'm so NOT here for that.
)
I'm still mad that she didn't record "Titanium" 