Comedians Bill Cosby and Chevy Chase, rock star Peter Frampton and "L.A. Law" star Jimmy Smits are helping Boys Town publicize a 24-hour, nationwide hot line for troubled youth.

Other celebrities helping include singers Lisa Lisa and Debbie Gibson, former baseball player Reggie Jackson and actors Michael Landon and Edward James Olmos.Thanks to the celebrities' public service announcements and signs advertising the toll-free number around the country, calls have steadily increased since it opened in May 1989, Boys Town officials said.

Boys Town, a home for troubled youngsters near Omaha, Neb., received about 233,000 telephone calls in 1990, said Constance Garrett, hot line director.