time series is going to kick off with a performance by Jay-Z, Rihanna and Kanye West. NBC said the three singers will perform together on “Run This Town,” a tune from Jay-Z's new album, on the Sept. 14 debut of “The Jay Leno Show.” The network and Leno said this week that there will be fewer musical acts. They also said he will feature interesting combinations of performers. Leno stepped down as “Tonight” host in May. He said that he'll expect guests on his new show to do more than talk — like, for example, race electric cars on a track being built near his NBC studio in Burbank. Leno, looking relaxed and trim - the result of running four miles (6.5 kilometers) a day, he said - told the Television Critics Association on Wednesday that fall's “The Jay Leno Show” will feature some elements from his old home, “Tonight,” but in a far different mix. Leno described himself as getting complacent after 17 years on “Tonight” and said he's excited about the challenge of creating a new show that represents a major change in network programming, taking a 10 p.m. EDT slot typically filled by hourlong drama series. “If we go down in flames, I'll be laughing,” Leno said.