Will and Zach united on red carpet

Will Ferrell and Zach Galifianakis stood united on the red carpet at the Hollywood premiere of their new comedy The Campaign.

In the film the pair are deadly enemies, as rival politicians running for congress in a fictional district of North Carolina, with Will starring as Democrat Cam Brady, and Zach running against him as Tea Party-style Republican Marty Huggins.

The pair were joined at the premiere at Grauman's Chinese Theatre in Hollywood by director Jay Roach and co-stars Dylan McDermott and Brian Cox.

In the film, long-term congressman Brady commits a major public gaffe before an upcoming election, prompting a pair of wealthy businessmen to put up a rival candidate and gain influence.

Local tourism centre director Huggins at first appears to be no competition, but with financial backing, a cut-throat campaign manager and his family's political connections, he becomes a threat, and the numbskull politicians are soon slinging mud at one another with hilarious consequences.

Meanwhile, Variety has revealed that Will has signed up to be reunited with his Wedding Crashers co-stars Owen Wilson and Vince Vaughn in The Internship.

Shawn Levy is directing the comedy about two unemployed salesmen who decide to reinvent themselves by becoming interns at a major technology company.

Will has agreed to cameo as Owen's character's brother-in-law, who sells home electronics and has no problem making inappropriate comments about his attractive customers.