Actors Sivakarthikeyan and Nayanthara will join hands for the first time for a yet-untitled Tamil project which will be directed Mohan Raja."The makers were in talks with three heroines, with Nayanthara being the front-runner. Since she had previously worked with director Mohan Raja in 'Thani Oruvan', she jumped at the opportunity the moment she heard the script," a source from the film's unit told IANS.Slated to go on the floors later this year, the rest of the cast and crew of the project are yet to be finalised.Sivakarthikeyan is currently busy shooting Tamil romantic-comedy "Remo", while Nayanthara is shooting for a yet-untitled Tamil thriller.