In his 11 years hosting ''The Tonight Show,'' Jay Leno has accomplished the Cal Ripken-like feat of never taking a sick day and never having a substitute host. However, he will turn over his desk to a guest host for one night, May 12, in a job swap with fellow NBC mainstay Katie Couric. Leno told TV's ''Access Hollywood'' on Thursday that the switch was the ''Today'' anchor's idea. ''She called me up and said let's switch places,'' Leno said. ''I have to put on panty hose and a bra, and she'll come here.''
Leno said he expects Couric to have an easier time making small talk with celebrities (something she does frequently on ''Today'' anyway) than he will rising at 3:30 a.m. (his usual bedtime, he says) and interrogating newsmakers. He says of his own show, ''We have it set up deliberately like a nightclub, so you play it the way you play a nightclub. I think she’ll do fine. People like her. She has an infectious personality, and she's so cute that if she bombs, she can get away with it because she's cute. If I bomb, it’s 'boo, hiss.'''