Rihanna, Kanye and Jay-Z to open new Jay Leno show

Rihanna poses with her awards for favorite female artist in the pop/rock and the soul/R&B categories at the 2008 American Music Awards in Los Angeles November 23, 2008.

LOS ANGELES (Reuters) - R&B stars Rihanna, Kanye West and Jay-Z will perform on the premiere of Jay Leno's comedy and chat show in September, in a apparent bid to grab hip, young viewers to NBC's new primetime experiment.

NBC said on Thursday that the trio would perform "Run This Town" from Jay-Z's new album, "The Blueprint 3," when "The Jay Leno Show" makes its debut on September 14 at 10pm.

It will be one of the first, major public performances for Rihanna, 21, since she was assaulted in February by her then boyfriend, singer Chris Brown.

Rihanna, rapper West and Jay-Z are among the most popular R&B artists in the United States.

NBC's decision to move the popular late night talk show host to the primetime slot five days a week is being closely watched by the U.S. TV industry as it seeks to trim costs and retain audiences.

Leno told reporters this week that his show would have more comedy and less chat. New features include a "green car" challenge in which celebrities will be invited to race a high-tech electric car round a track built outside Leno's new studio.

Brown has pleaded guilty to punching Rihanna in Los Angeles in February and is expected to be sentenced later this month to five years probation and 180 days of community service.

(Editing by Bob Tourtellotte)