Johnny Carson has signed up for his 30th year as host of NBC's "Tonight" show in a one-year contract that goes into effect when his current contract expires at the end of September, it was announced Monday.

Brandon Tartikoff, chairman, NBC Entertainment Group, made the announcement and revealed that Carson, 65, had expressed a desire to step down from the late night show before the end of 1991.Comedian Jay Leno, exclusive guest host of "The Tonight Show," had been rumored to be taking over for Carson because the network wanted a host who would appeal to a younger audience, but Tartikoff has always denied this.

Tartikoff said Monday that getting Carson back was a top priority and he added:

"After several conversations between us, Johnny agreed to continue and I'm thrilled he's decided to celebrate his 30th anniversary year with us and to continue entertaining the American television audience as only he can."

NBC would not reveal how much the network was paying Carson.

Nearly 12 million viewers watch "The Tonight Show" each night, according to NBC. Since Carson took over on Oct. 1, 1962, he has been the host of nearly 7,500 hours of shows and introduced more than 21,000 guests - from stars of the entertainment business to just plain folks.

"Tonight" was the original desk-and-sofa late night show, premiering on NBC Sept. 27, 1954 as a 90-min-ute showcase for Steve Allen. Jack Paar took over in 1957 and Carson became host in 1962. The show was based in New York until 1971, when Carson moved it to the NBC studios in Burbank, Calif.

The show has dominated the late night field from its inception and "The Tonight Show With Johnny Carson," as it is now titled, has not loosened NBC's hold on the time period.