Justin Timberlake, Ben Affleck to star in "Runner, Runner" .

Singer-turned-actor Justin Timberlake is all set to star opposite Ben Affleck in a dramatic thriller `Runner, Runner`.

The 31-year-old is finalizing his negotiation to join the movie, which will be directed by "The Lincoln Lawyer" helmer Brad Furman, reported Aceshowbiz.

Storyline of `Runner, Runner` remains scarce for now, but it is said that the movie will be set in a world of illegal online gambling.

The screenplay is written by scribe duo Brian Koppelman and David Levien, who also wrote 1998`s `Rounders` about the underground world of high-stakes poker.

Producing the upcoming thriller are Leonardo DiCaprio and Jennifer Killoran, as well as Double Feature`s Michael Shambeg and Stacey Sher.

Timberlake will also be seen in `Trouble with the Curve` opposite Clint Eastwood and Coen brothers` folk music film `Inside Llewyn Davis`. Affleck, on the other hand, is finishing his latest directorial debut `Argo`, which will hit the US theaters on October 12.