John Lithgow joins Will Ferrell's political comedy Dog Fight

John Lithgow has joined the impressive cast list of political comedy Dog Fight (formerly Southern Rivals ).

The Leap Year actor joins Will Ferrell and Zach Galifianakis, as well as his Rise Of The Planet Of The Apes castmate Brian Cox, in the comedy.

Will Ferrell and Zach Galifianakis play two less-than-adequate politicians who are fighting over a seat in the North Carolina district election.

As yet John Lithgow's role in the movie is yet to be announced.

Dinner For Schmucks director Jay Roach will be directing Dog Figh t , which is due to be released in August next year.

John Lithgow can next be seen with Robert De Niro and a coachload of other big names in New Year's Eve , which opens on 8 December 2011 .