IN what has become the No. 1 viral video war of 2008, U.S. TV host Jimmy Kimmel hit back at girlfriend Sarah Silverman’s humorous music video confession that she was having an affair with actor Matt Damon with his own star-studded music video claiming he has sex with actor Ben Affleck.

The late night host called on a string of U.S. celebrities, including Brad Pitt, Cameron Diaz, Robin Williams and Harrison Ford, to sing a “We are the World”-type chorus, which aired Feb. 24 after the Oscars on ABC’s “Jimmy Kimmel Live.”

As of Tuesday afternoon, the four-minute video had been viewed more than 2.5 million times on YouTube. It has also been prominently displayed on the broadcast network’s home page, ABC.com.

The “relationship” has not been a secret since at least Feb. 15, when The New York Post reported that Kimmel was preparing a star-studded video, reminiscent of “We Are the World,” as a reply to a similar video presented on his show last month by comedian Silverman.

Silverman, who is Kimmel’s longtime girlfriend, unveiled her video, in which she confesses that she has been sleeping with Damon, on Kimmel’s fifth-anniversary show Jan. 31. That video has been viewed more than 8 million times on YouTube.

For many Kimmel fans, his video was just the latest salvo in the long-running “feud” between Damon and Kimmel. It all started during the third season of ABC’s “Jimmy Kimmel Live,” when the host made a habit of closing out episodes with, “Apologies to Matt Damon, but we ran out of time,” even though the actor was never scheduled to come on the show.

The joke continued in September 2006 when Damon finally appeared as a guest. After a segment which explained the gag and a lengthy introduction by Kimmel, Damon sat down, only to have the host cut him off and end the show. As planned, the actor unleashed a flurry of curse words on Kimmel and proceeded to storm off the set. His performance was so realistic, many fans thought he was truly upset.(SD-Agencies)