FIRST OFF . . .

“Comic Relief III,” the third superstar benefit performance to raise awareness and funds to help America’s homeless, will be held March 18 at Universal Amphitheatre, it was announced Tuesday. The 6 p.m. event--hosted, as was the case with the first “Comic Relief,” by Billy Crystal, Whoopi Goldberg and Robin Williams--will be broadcast live by the event’s presenter, HBO. The two previous “Comic Reliefs”--in 1986 and ‘87--raised more than $4.7 million for health care and related services for more than 150,000 homeless Americans. During the presentation, HBO will open up its signal so that affiliates can carry the show--which will feature a toll-free number for viewers to call in pledges--on basic cable and thus reach a larger share of the public. Said “Comic Relief” president Bob Zmuda: “‘Comic Relief’ has had a significant impact around the country. With 23 cities now receiving money . . . we are proud that the comedy community has given so generously to this important cause.” Tickets for the performance are scheduled to go on sale the first week of February.